From ed38456f83ac84ab1f3facc52de83f4e58a78f18 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Fri, 15 Apr 2022 20:46:40 +0100
Subject: [PATCH 01/33] Piggy-back 'Do not remove trailing 0xff' onto option -D

---
 src/avr.c    | 10 ++++++++++
 src/fileio.c |  5 ++++-
 src/main.c   |  1 +
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/avr.c b/src/avr.c
index d6e78bb5..9d2bf503 100644
--- a/src/avr.c
+++ b/src/avr.c
@@ -282,6 +282,16 @@ int avr_read_byte_default(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 int avr_mem_hiaddr(AVRMEM * mem)
 {
   int i, n;
+  static int disableffopt;
+
+  /* calling once with NULL disables any future trailing-0xff optimisation */
+  if(!mem) {
+    disableffopt = 1;
+    return 0;
+  }
+
+  if(disableffopt)
+    return mem->size;
 
   /* return the highest non-0xff address regardless of how much
      memory was read */
diff --git a/src/fileio.c b/src/fileio.c
index 7c021ce4..429a200e 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -1594,7 +1594,10 @@ int fileio(int op, char * filename, FILEFMT format,
        * if we are reading flash, just mark the size as being the
        * highest non-0xff byte
        */
-      rc = avr_mem_hiaddr(mem);
+      int hiaddr = avr_mem_hiaddr(mem);
+
+      if(hiaddr < rc)           /* if trailing-0xff not disabled */
+        rc = hiaddr;
     }
   }
   if (format != FMT_IMM && !using_stdio) {
diff --git a/src/main.c b/src/main.c
index 253c6e51..c3bc0381 100644
--- a/src/main.c
+++ b/src/main.c
@@ -528,6 +528,7 @@ int main(int argc, char * argv [])
 
       case 'D': /* disable auto erase */
         uflags &= ~UF_AUTO_ERASE;
+        avr_mem_hiaddr(NULL); /* disable trailing 0xff optimisation */
         break;
 
       case 'e': /* perform a chip erase */

From e18d436f88e575afcee68343842660b44aa9ce30 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Fri, 15 Apr 2022 20:48:46 +0100
Subject: [PATCH 02/33] Move evaluating 'is flash' from caller to callee
 avr_mem_hiaddr()

---
 src/avr.c    | 27 +++++++++++----------------
 src/fileio.c | 19 ++++++-------------
 2 files changed, 17 insertions(+), 29 deletions(-)

diff --git a/src/avr.c b/src/avr.c
index 9d2bf503..a6d621b7 100644
--- a/src/avr.c
+++ b/src/avr.c
@@ -278,6 +278,7 @@ int avr_read_byte_default(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
  * value. This is useful for determining where to stop when dealing
  * with "flash" memory, since writing 0xff to flash is typically a
  * no-op. Always return an even number since flash is word addressed.
+ * Only apply this optimisation on flash-type memory.
  */
 int avr_mem_hiaddr(AVRMEM * mem)
 {
@@ -293,6 +294,13 @@ int avr_mem_hiaddr(AVRMEM * mem)
   if(disableffopt)
     return mem->size;
 
+  /* if the memory is not a flash-type memory do not remove trailing 0xff */
+  if(strcasecmp(mem->desc, "flash") &&
+     strcasecmp(mem->desc, "application") &&
+     strcasecmp(mem->desc, "apptable") &&
+     strcasecmp(mem->desc, "boot"))
+    return mem->size;
+
   /* return the highest non-0xff address regardless of how much
      memory was read */
   for (i=mem->size-1; i>0; i--) {
@@ -426,15 +434,8 @@ int avr_read(PROGRAMMER * pgm, AVRPART * p, char * memtype,
       nread++;
       report_progress(nread, npages, NULL);
     }
-    if (!failure) {
-      if (strcasecmp(mem->desc, "flash") == 0 ||
-          strcasecmp(mem->desc, "application") == 0 ||
-          strcasecmp(mem->desc, "apptable") == 0 ||
-          strcasecmp(mem->desc, "boot") == 0)
-        return avr_mem_hiaddr(mem);
-      else
-        return mem->size;
-    }
+    if (!failure)
+      return avr_mem_hiaddr(mem);
     /* else: fall back to byte-at-a-time write, for historical reasons */
   }
 
@@ -464,13 +465,7 @@ int avr_read(PROGRAMMER * pgm, AVRPART * p, char * memtype,
     report_progress(i, mem->size, NULL);
   }
 
-  if (strcasecmp(mem->desc, "flash") == 0 ||
-      strcasecmp(mem->desc, "application") == 0 ||
-      strcasecmp(mem->desc, "apptable") == 0 ||
-      strcasecmp(mem->desc, "boot") == 0)
-    return avr_mem_hiaddr(mem);
-  else
-    return i;
+  return avr_mem_hiaddr(mem);
 }
 
 
diff --git a/src/fileio.c b/src/fileio.c
index 429a200e..754e267b 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -1585,21 +1585,14 @@ int fileio(int op, char * filename, FILEFMT format,
       return -1;
   }
 
-  if (rc > 0) {
-    if ((op == FIO_READ) && (strcasecmp(mem->desc, "flash") == 0 ||
-                             strcasecmp(mem->desc, "application") == 0 ||
-                             strcasecmp(mem->desc, "apptable") == 0 ||
-                             strcasecmp(mem->desc, "boot") == 0)) {
-      /*
-       * if we are reading flash, just mark the size as being the
-       * highest non-0xff byte
-       */
-      int hiaddr = avr_mem_hiaddr(mem);
+  /* on reading flash set the size to location of highest non-0xff byte */
+  if (rc > 0 && op == FIO_READ) {
+    int hiaddr = avr_mem_hiaddr(mem);
 
-      if(hiaddr < rc)           /* if trailing-0xff not disabled */
-        rc = hiaddr;
-    }
+    if(hiaddr < rc)             /* if trailing-0xff not disabled */
+      rc = hiaddr;
   }
+
   if (format != FMT_IMM && !using_stdio) {
     fclose(f);
   }

From 2397984d2b13b885fee4100f79af6612dca33599 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Wed, 27 Apr 2022 18:54:13 +0100
Subject: [PATCH 03/33] Disable trailing-0xff removal when invoking arduino
 programmer

---
 src/arduino.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/arduino.c b/src/arduino.c
index dbaafef2..7f030a13 100644
--- a/src/arduino.c
+++ b/src/arduino.c
@@ -130,4 +130,7 @@ void arduino_initpgm(PROGRAMMER * pgm)
   pgm->read_sig_bytes = arduino_read_sig_bytes;
   pgm->open = arduino_open;
   pgm->close = arduino_close;
+
+  /* disable trailing-0xff removal when reading input files and avr flash */
+  avr_mem_hiaddr(NULL);
 }

From 52b20f4a2808dc6732fd9d185a9f0b3c1122b7e0 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Thu, 28 Apr 2022 17:26:09 +0100
Subject: [PATCH 04/33] Provide self-documenting API for disabling
 trailing-0xff removal

---
 src/arduino.c    | 3 +--
 src/libavrdude.h | 1 +
 src/main.c       | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/arduino.c b/src/arduino.c
index 7f030a13..f7b60246 100644
--- a/src/arduino.c
+++ b/src/arduino.c
@@ -131,6 +131,5 @@ void arduino_initpgm(PROGRAMMER * pgm)
   pgm->open = arduino_open;
   pgm->close = arduino_close;
 
-  /* disable trailing-0xff removal when reading input files and avr flash */
-  avr_mem_hiaddr(NULL);
+  disable_trailing_ff_removal(); /* so that arduino bootloader can ignore chip erase */
 }
diff --git a/src/libavrdude.h b/src/libavrdude.h
index ddb72b48..d8d5739a 100644
--- a/src/libavrdude.h
+++ b/src/libavrdude.h
@@ -787,6 +787,7 @@ int avr_get_cycle_count(PROGRAMMER * pgm, AVRPART * p, int * cycles);
 
 int avr_put_cycle_count(PROGRAMMER * pgm, AVRPART * p, int cycles);
 
+#define disable_trailing_ff_removal() avr_mem_hiaddr(NULL)
 int avr_mem_hiaddr(AVRMEM * mem);
 
 int avr_chip_erase(PROGRAMMER * pgm, AVRPART * p);
diff --git a/src/main.c b/src/main.c
index c3bc0381..526ae35f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -528,7 +528,7 @@ int main(int argc, char * argv [])
 
       case 'D': /* disable auto erase */
         uflags &= ~UF_AUTO_ERASE;
-        avr_mem_hiaddr(NULL); /* disable trailing 0xff optimisation */
+        disable_trailing_ff_removal();
         break;
 
       case 'e': /* perform a chip erase */

From 52734bafc6af7cfc4b72824629159900ee88f6a6 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Thu, 28 Apr 2022 17:29:06 +0100
Subject: [PATCH 05/33] Add option -A to separately disable trailing-0xff
 removal

---
 src/main.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/main.c b/src/main.c
index 526ae35f..f5381834 100644
--- a/src/main.c
+++ b/src/main.c
@@ -110,7 +110,8 @@ static void usage(void)
  "  -B <bitclock>              Specify JTAG/STK500v2 bit clock period (us).\n"
  "  -C <config-file>           Specify location of configuration file.\n"
  "  -c <programmer>            Specify programmer type.\n"
- "  -D                         Disable auto erase for flash memory\n"
+ "  -A                         Disable trailing-0xff removal from file and AVR read.\n"
+ "  -D                         Disable auto erase for flash memory; implies -A.\n"
  "  -i <delay>                 ISP Clock Delay [in microseconds]\n"
  "  -P <port>                  Specify connection port.\n"
  "  -F                         Override invalid signature check.\n"
@@ -442,7 +443,7 @@ int main(int argc, char * argv [])
   /*
    * process command line arguments
    */
-  while ((ch = getopt(argc,argv,"?b:B:c:C:DeE:Fi:l:np:OP:qstU:uvVx:yY:")) != -1) {
+  while ((ch = getopt(argc,argv,"?Ab:B:c:C:DeE:Fi:l:np:OP:qstU:uvVx:yY:")) != -1) {
 
     switch (ch) {
       case 'b': /* override default programmer baud rate */
@@ -528,6 +529,9 @@ int main(int argc, char * argv [])
 
       case 'D': /* disable auto erase */
         uflags &= ~UF_AUTO_ERASE;
+        /* fall through */
+
+      case 'A': /* explicit disabling of trailing-0xff removal */
         disable_trailing_ff_removal();
         break;
 

From f47ec634f81a0f9bd89aa6ce0616b147f69da5d9 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Thu, 28 Apr 2022 17:53:10 +0100
Subject: [PATCH 06/33] On verify always verify full input file

---
 src/fileio.c     | 9 +++++----
 src/libavrdude.h | 5 +++--
 src/update.c     | 2 +-
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/fileio.c b/src/fileio.c
index 754e267b..1c81682d 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -1446,16 +1446,17 @@ static int fmt_autodetect(char * fname)
 
 
 
-int fileio(int op, char * filename, FILEFMT format, 
+int fileio(int oprwv, char * filename, FILEFMT format,
              struct avrpart * p, char * memtype, int size)
 {
-  int rc;
+  int op, rc;
   FILE * f;
   char * fname;
   struct fioparms fio;
   AVRMEM * mem;
   int using_stdio;
 
+  op = oprwv == FIO_READ_FOR_VERIFY? FIO_READ: oprwv;
   mem = avr_locate_mem(p, memtype);
   if (mem == NULL) {
     avrdude_message(MSG_INFO, "fileio(): memory type \"%s\" not configured for device \"%s\"\n",
@@ -1585,8 +1586,8 @@ int fileio(int op, char * filename, FILEFMT format,
       return -1;
   }
 
-  /* on reading flash set the size to location of highest non-0xff byte */
-  if (rc > 0 && op == FIO_READ) {
+  /* on reading flash other than for verify set the size to location of highest non-0xff byte */
+  if (rc > 0 && oprwv == FIO_READ) {
     int hiaddr = avr_mem_hiaddr(mem);
 
     if(hiaddr < rc)             /* if trailing-0xff not disabled */
diff --git a/src/libavrdude.h b/src/libavrdude.h
index d8d5739a..73083932 100644
--- a/src/libavrdude.h
+++ b/src/libavrdude.h
@@ -826,7 +826,8 @@ struct fioparms {
 
 enum {
   FIO_READ,
-  FIO_WRITE
+  FIO_WRITE,
+  FIO_READ_FOR_VERIFY,
 };
 
 #ifdef __cplusplus
@@ -835,7 +836,7 @@ extern "C" {
 
 char * fmtstr(FILEFMT format);
 
-int fileio(int op, char * filename, FILEFMT format,
+int fileio(int oprwv, char * filename, FILEFMT format,
            struct avrpart * p, char * memtype, int size);
 
 #ifdef __cplusplus
diff --git a/src/update.c b/src/update.c
index 15002549..d3c208fc 100644
--- a/src/update.c
+++ b/src/update.c
@@ -341,7 +341,7 @@ int do_op(PROGRAMMER * pgm, struct avrpart * p, UPDATE * upd, enum updateflags f
             progname, mem->desc, alias_mem_desc, upd->filename);
     }
 
-    rc = fileio(FIO_READ, upd->filename, upd->format, p, upd->memtype, -1);
+    rc = fileio(FIO_READ_FOR_VERIFY, upd->filename, upd->format, p, upd->memtype, -1);
     if (rc < 0) {
       avrdude_message(MSG_INFO, "%s: read from file '%s' failed\n",
               progname, upd->filename);

From 580c37fbfefcff83131ea767b176cbf27f9a39a8 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Fri, 29 Apr 2022 00:14:45 +0100
Subject: [PATCH 07/33] Describe -A in the man and .texi documentation

---
 src/avrdude.1        | 25 ++++++++++++++++++++++---
 src/doc/avrdude.texi | 15 +++++++++++++--
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/avrdude.1 b/src/avrdude.1
index cc05cf4c..48082d00 100644
--- a/src/avrdude.1
+++ b/src/avrdude.1
@@ -18,7 +18,7 @@
 .\"
 .\" $Id$
 .\"
-.Dd DATE November 22, 2021
+.Dd DATE April 28, 2022
 .Os
 .Dt AVRDUDE 1
 .Sh NAME
@@ -31,6 +31,7 @@
 .Op Fl B Ar bitclock
 .Op Fl c Ar programmer-id
 .Op Fl C Ar config-file
+.Op Fl A
 .Op Fl D
 .Op Fl e
 .Oo Fl E Ar exitspec Ns
@@ -102,7 +103,7 @@ available (like almost all embedded Linux boards) you can do without
 any additional hardware - just connect them to the MOSI, MISO, RESET 
 and SCK pins on the AVR and use the linuxgpio programmer type. It bitbangs
 the lines using the Linux sysfs GPIO interface. Of course, care should
-be taken about voltage level compatibility. Also, although not strictrly 
+be taken about voltage level compatibility. Also, although not strictly
 required, it is strongly advisable to protect the GPIO pins from 
 overcurrent situations in some way. The simplest would be to just put
 some resistors in series or better yet use a 3-state buffer driver like
@@ -253,7 +254,7 @@ The Teensy bootloader is supported for all AVR boards.
 As the bootloader does not support reading from flash memory,
 use the
 .Fl V
-option to prevent AVRDUDE from verifing the flash memory.
+option to prevent AVRDUDE from verifying the flash memory.
 See the section on
 .Em extended parameters
 for Teensy specific options.
@@ -376,6 +377,20 @@ files. This can be used to add entries to the configuration
 without patching your system wide configuration file. It can be used
 several times, the files are read in same order as given on the command
 line.
+.It Fl A
+Disable the automatic removal of trailing-0xFF sequences in file
+input that is to be programmed to flash and in AVR reads from
+flash memory. Normally, trailing 0xFFs can be discarded, as flash
+programming requires the memory be erased to 0xFF beforehand.
+.Fl A
+should be used when the programmer hardware, or bootloader
+software for that matter, does not carry out chip erase and
+instead handles the memory erase on a page level. The popular
+Arduino bootloader exhibits this behaviour; for this reason
+.Fl A
+is engaged by default when specifying
+. Fl c
+arduino.
 .It Fl D
 Disable auto erase for flash.  When the
 .Fl U
@@ -389,6 +404,10 @@ use page erase before writing each page so no explicit chip erase
 is required.
 Note however that any page not affected by the current operation
 will retain its previous contents.
+Setting
+.Fl D
+implies
+.Fl A.
 .It Fl e
 Causes a chip erase to be executed.  This will reset the contents of the
 flash ROM and EEPROM to the value
diff --git a/src/doc/avrdude.texi b/src/doc/avrdude.texi
index ad4a6598..a7901361 100644
--- a/src/doc/avrdude.texi
+++ b/src/doc/avrdude.texi
@@ -321,13 +321,13 @@ via a serial link (@url{https://github.com/ElTangas/jtag2updi}).
 
 The Micronucleus bootloader is supported for both protocol version V1
 and V2. As the bootloader does not support reading from flash memory,
-use the @code{-V} option to prevent AVRDUDE from verifing the flash memory.
+use the @code{-V} option to prevent AVRDUDE from verifying the flash memory.
 See the section on @emph{extended parameters}
 below for Micronucleus specific options.
 
 The Teensy bootloader is supported for all AVR boards.
 As the bootloader does not support reading from flash memory,
-use the @code{-V} option to prevent AVRDUDE from verifing the flash memory.
+use the @code{-V} option to prevent AVRDUDE from verifying the flash memory.
 See the section on @emph{extended parameters}
 below for Teensy specific options.
 
@@ -495,6 +495,16 @@ without patching your system wide configuration file. It can be used
 several times, the files are read in same order as given on the command 
 line.
 
+@item -A
+Disable the automatic removal of trailing-0xFF sequences in file
+input that is to be programmed to flash and in AVR reads from
+flash memory. Normally, trailing 0xFFs can be discarded, as flash
+programming requires the memory be erased to 0xFF beforehand. -A
+should be used when the programmer hardware, or bootloader
+software for that matter, does not carry out chip erase and
+instead handles the memory erase on a page level. The popular
+Arduino bootloader exhibits this behaviour; for this reason -A is
+engaged by default when specifying -c arduino.
 
 @item -D
 Disable auto erase for flash.  When the -U option with flash memory is 
@@ -506,6 +516,7 @@ use page erase before writing each page so no explicit chip erase
 is required.
 Note however that any page not affected by the current operation
 will retain its previous contents.
+Setting -D implies -A.
 
 @item -e
 Causes a chip erase to be executed.  This will reset the contents of the

From c8350f816c2ec26022bba5758aadebd4b3095230 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Sat, 18 Jun 2022 22:34:54 +0100
Subject: [PATCH 08/33] Fix support for ATmega2560 et al (load extended
 address)

---
 src/avrftdi.c         | 41 +++++++++++++++++++----------------------
 src/avrftdi_private.h |  2 ++
 2 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/src/avrftdi.c b/src/avrftdi.c
index e41d775e..c6d2f86e 100644
--- a/src/avrftdi.c
+++ b/src/avrftdi.c
@@ -917,8 +917,15 @@ static int avrftdi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
 static int
 avrftdi_lext(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m, unsigned int address)
 {
+	avrftdi_t *pdata = to_pdata(pgm);
 	unsigned char buf[] = { 0x00, 0x00, 0x00, 0x00 };
 
+	/* only send load extended address command if high byte changed */
+	if(pdata->lext_byte == (uint8_t) (address>>16))
+		return 0;
+
+	pdata->lext_byte = (uint8_t) (address>>16);
+
 	avr_set_bits(m->op[AVR_OP_LOAD_EXT_ADDR], buf);
 	avr_set_addr(m->op[AVR_OP_LOAD_EXT_ADDR], buf, address);
 
@@ -983,8 +990,6 @@ static int avrftdi_eeprom_read(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
 static int avrftdi_flash_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 		unsigned int page_size, unsigned int addr, unsigned int len)
 {
-	int use_lext_address = m->op[AVR_OP_LOAD_EXT_ADDR] != NULL;
-	
 	unsigned int word;
 	unsigned int poll_index;
 
@@ -1013,22 +1018,12 @@ static int avrftdi_flash_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 
 	page_size = m->page_size;
 
-	/* if we do cross a 64k word boundary (or write the
-	 * first page), we need to issue a 'load extended
-	 * address byte' command, which is defined as 0x4d
-	 * 0x00 <address byte> 0x00.  As far as i know, this
-	 * is only available on 256k parts.  64k word is 128k
-	 * bytes.
-	 * write the command only once.
-	 */
-	if(use_lext_address && (((addr/2) & 0xffff0000))) {
-		if (0 > avrftdi_lext(pgm, p, m, addr/2))
-			return -1;
-	}
+	/* on large-flash devices > 128k issue extended address command when needed */
+	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, addr/2) < 0)
+		return -1;
 	
 	/* prepare the command stream for the whole page */
-	/* addr is in bytes, but we program in words. addr/2 should be something
-	 * like addr >> WORD_SHIFT, though */
+	/* addr is in bytes, but we program in words. */
 	for(word = addr/2; word < (len + addr)/2; word++)
 	{
 		log_debug("-< bytes = %d of %d\n", word * 2, len + addr);
@@ -1107,7 +1102,6 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 {
 	OPCODE * readop;
 	int byte, word;
-	int use_lext_address = m->op[AVR_OP_LOAD_EXT_ADDR] != NULL;
 	unsigned int address = addr/2;
 
 	unsigned int buf_size = 4 * len + 4;
@@ -1128,10 +1122,8 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 		return -1;
 	}
 	
-	if(use_lext_address && ((address & 0xffff0000))) {
-		if (0 > avrftdi_lext(pgm, p, m, address))
-			return -1;
-	}
+	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, address) < 0)
+		return -1;
 	
 	/* word addressing! */
 	for(word = addr/2, index = 0; word < (addr + len)/2; word++)
@@ -1210,7 +1202,11 @@ avrftdi_setup(PROGRAMMER * pgm)
 {
 	avrftdi_t* pdata;
 
-	pgm->cookie = malloc(sizeof(avrftdi_t));
+	
+	if(!(pgm->cookie = calloc(sizeof(avrftdi_t), 1))) {
+		log_err("Error allocating memory.\n");
+		exit(1);
+	}
 	pdata = to_pdata(pgm);
 
 	pdata->ftdic = ftdi_new();
@@ -1224,6 +1220,7 @@ avrftdi_setup(PROGRAMMER * pgm)
 	pdata->pin_value = 0;
 	pdata->pin_direction = 0;
 	pdata->led_mask = 0;
+	pdata->lext_byte = 0xff;
 }
 
 static void
diff --git a/src/avrftdi_private.h b/src/avrftdi_private.h
index 3c965ed8..15b9caec 100644
--- a/src/avrftdi_private.h
+++ b/src/avrftdi_private.h
@@ -81,6 +81,8 @@ typedef struct avrftdi_s {
 	int tx_buffer_size;
 	/* use bitbanging instead of mpsse spi */
 	bool use_bitbanging;
+	/* bits 16-23 of extended 24-bit word flash address for parts with flash > 128k */
+	uint8_t lext_byte;
 } avrftdi_t;
 
 void avrftdi_log(int level, const char * func, int line, const char * fmt, ...);

From aa211f75800d320548cc051c8f830886f4f09c7e Mon Sep 17 00:00:00 2001
From: MCUdude <hansibull@gmail.com>
Date: Sun, 19 Jun 2022 19:23:34 +0200
Subject: [PATCH 09/33] Add missing efuse write delay for ATmega169/A/P/PA and
 ATmega328P

---
 src/avrdude.conf.in | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/avrdude.conf.in b/src/avrdude.conf.in
index 362b6167..c0ba9c4b 100644
--- a/src/avrdude.conf.in
+++ b/src/avrdude.conf.in
@@ -5823,6 +5823,8 @@ part
 
     memory "efuse"
         size            = 1;
+        min_write_delay = 2000;
+        max_write_delay = 2000;
         write           = "1 0 1 0  1 1 0 0  1 0 1 0  0 1 0 0",
                           "x x x x  x x x x  x x x x  i i i i";
 
@@ -9852,6 +9854,8 @@ part parent "m328"
 
     memory "efuse"
         size = 1;
+        min_write_delay = 4500;
+        max_write_delay = 4500;
         read            = "0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0",
                           "x x x x x x x x o o o o o o o o";
         write           = "1 0 1 0 1 1 0 0 1 0 1 0 0 1 0 0",

From 692c13ed98a80b0728f2a4e78c6b61fcf181fa3b Mon Sep 17 00:00:00 2001
From: MCUdude <hansibull@gmail.com>
Date: Sun, 19 Jun 2022 19:40:31 +0200
Subject: [PATCH 10/33] Add missing chip erase delay for ATmega48/88/168/328PB

---
 src/avrdude.conf.in | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/avrdude.conf.in b/src/avrdude.conf.in
index c0ba9c4b..bf2892aa 100644
--- a/src/avrdude.conf.in
+++ b/src/avrdude.conf.in
@@ -8215,6 +8215,7 @@ part parent "m48"
     id               = "m48pb";
     desc             = "ATmega48PB";
     signature        = 0x1e 0x92 0x10;
+    chip_erase_delay = 10500;
   ;
 
 #------------------------------------------------------------
@@ -8442,6 +8443,7 @@ part parent "m88"
     id               = "m88pb";
     desc             = "ATmega88PB";
     signature        = 0x1e 0x93 0x16;
+    chip_erase_delay = 10500;
   ;
 
 #------------------------------------------------------------
@@ -8671,6 +8673,7 @@ part parent "m168"
     id              = "m168pb";
     desc            = "ATmega168PB";
     signature       = 0x1e 0x94 0x15;
+    chip_erase_delay = 10500;
   ;
 
 #------------------------------------------------------------
@@ -9827,6 +9830,7 @@ part parent "m328"
     id              = "m328pb";
     desc            = "ATmega328PB";
     signature       = 0x1e 0x95 0x16;
+    chip_erase_delay = 10500;
 
     memory "efuse"
         size = 1;

From d95c1a91f72578a761c579b103c3a1c787a741e1 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Mon, 4 Jul 2022 12:25:50 +0100
Subject: [PATCH 11/33] Steamline avrftdi support for ATmega2560 et al

---
 src/avrftdi.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/avrftdi.c b/src/avrftdi.c
index c6d2f86e..54490dc0 100644
--- a/src/avrftdi.c
+++ b/src/avrftdi.c
@@ -917,6 +917,10 @@ static int avrftdi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
 static int
 avrftdi_lext(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m, unsigned int address)
 {
+	/* nothing to do if load extended address command unavailable */
+        if(m->op[AVR_OP_LOAD_EXT_ADDR] == NULL)
+		return 0;
+
 	avrftdi_t *pdata = to_pdata(pgm);
 	unsigned char buf[] = { 0x00, 0x00, 0x00, 0x00 };
 
@@ -1019,7 +1023,7 @@ static int avrftdi_flash_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 	page_size = m->page_size;
 
 	/* on large-flash devices > 128k issue extended address command when needed */
-	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, addr/2) < 0)
+	if(avrftdi_lext(pgm, p, m, addr/2) < 0)
 		return -1;
 	
 	/* prepare the command stream for the whole page */
@@ -1102,7 +1106,6 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 {
 	OPCODE * readop;
 	int byte, word;
-	unsigned int address = addr/2;
 
 	unsigned int buf_size = 4 * len + 4;
 	unsigned char* o_buf = alloca(buf_size);
@@ -1122,7 +1125,7 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 		return -1;
 	}
 	
-	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, address) < 0)
+	if(avrftdi_lext(pgm, p, m, addr/2) < 0)
 		return -1;
 	
 	/* word addressing! */

From 3893a21164c0adec19e5d29f34efddb9b007d56a Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Sat, 18 Jun 2022 22:34:54 +0100
Subject: [PATCH 12/33] Fix avrftdi support for ATmega2560 et al (load extended
 address)

---
 src/avrftdi.c         | 41 +++++++++++++++++++----------------------
 src/avrftdi_private.h |  2 ++
 2 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/src/avrftdi.c b/src/avrftdi.c
index e41d775e..c6d2f86e 100644
--- a/src/avrftdi.c
+++ b/src/avrftdi.c
@@ -917,8 +917,15 @@ static int avrftdi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
 static int
 avrftdi_lext(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m, unsigned int address)
 {
+	avrftdi_t *pdata = to_pdata(pgm);
 	unsigned char buf[] = { 0x00, 0x00, 0x00, 0x00 };
 
+	/* only send load extended address command if high byte changed */
+	if(pdata->lext_byte == (uint8_t) (address>>16))
+		return 0;
+
+	pdata->lext_byte = (uint8_t) (address>>16);
+
 	avr_set_bits(m->op[AVR_OP_LOAD_EXT_ADDR], buf);
 	avr_set_addr(m->op[AVR_OP_LOAD_EXT_ADDR], buf, address);
 
@@ -983,8 +990,6 @@ static int avrftdi_eeprom_read(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
 static int avrftdi_flash_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 		unsigned int page_size, unsigned int addr, unsigned int len)
 {
-	int use_lext_address = m->op[AVR_OP_LOAD_EXT_ADDR] != NULL;
-	
 	unsigned int word;
 	unsigned int poll_index;
 
@@ -1013,22 +1018,12 @@ static int avrftdi_flash_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 
 	page_size = m->page_size;
 
-	/* if we do cross a 64k word boundary (or write the
-	 * first page), we need to issue a 'load extended
-	 * address byte' command, which is defined as 0x4d
-	 * 0x00 <address byte> 0x00.  As far as i know, this
-	 * is only available on 256k parts.  64k word is 128k
-	 * bytes.
-	 * write the command only once.
-	 */
-	if(use_lext_address && (((addr/2) & 0xffff0000))) {
-		if (0 > avrftdi_lext(pgm, p, m, addr/2))
-			return -1;
-	}
+	/* on large-flash devices > 128k issue extended address command when needed */
+	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, addr/2) < 0)
+		return -1;
 	
 	/* prepare the command stream for the whole page */
-	/* addr is in bytes, but we program in words. addr/2 should be something
-	 * like addr >> WORD_SHIFT, though */
+	/* addr is in bytes, but we program in words. */
 	for(word = addr/2; word < (len + addr)/2; word++)
 	{
 		log_debug("-< bytes = %d of %d\n", word * 2, len + addr);
@@ -1107,7 +1102,6 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 {
 	OPCODE * readop;
 	int byte, word;
-	int use_lext_address = m->op[AVR_OP_LOAD_EXT_ADDR] != NULL;
 	unsigned int address = addr/2;
 
 	unsigned int buf_size = 4 * len + 4;
@@ -1128,10 +1122,8 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 		return -1;
 	}
 	
-	if(use_lext_address && ((address & 0xffff0000))) {
-		if (0 > avrftdi_lext(pgm, p, m, address))
-			return -1;
-	}
+	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, address) < 0)
+		return -1;
 	
 	/* word addressing! */
 	for(word = addr/2, index = 0; word < (addr + len)/2; word++)
@@ -1210,7 +1202,11 @@ avrftdi_setup(PROGRAMMER * pgm)
 {
 	avrftdi_t* pdata;
 
-	pgm->cookie = malloc(sizeof(avrftdi_t));
+	
+	if(!(pgm->cookie = calloc(sizeof(avrftdi_t), 1))) {
+		log_err("Error allocating memory.\n");
+		exit(1);
+	}
 	pdata = to_pdata(pgm);
 
 	pdata->ftdic = ftdi_new();
@@ -1224,6 +1220,7 @@ avrftdi_setup(PROGRAMMER * pgm)
 	pdata->pin_value = 0;
 	pdata->pin_direction = 0;
 	pdata->led_mask = 0;
+	pdata->lext_byte = 0xff;
 }
 
 static void
diff --git a/src/avrftdi_private.h b/src/avrftdi_private.h
index 3c965ed8..15b9caec 100644
--- a/src/avrftdi_private.h
+++ b/src/avrftdi_private.h
@@ -81,6 +81,8 @@ typedef struct avrftdi_s {
 	int tx_buffer_size;
 	/* use bitbanging instead of mpsse spi */
 	bool use_bitbanging;
+	/* bits 16-23 of extended 24-bit word flash address for parts with flash > 128k */
+	uint8_t lext_byte;
 } avrftdi_t;
 
 void avrftdi_log(int level, const char * func, int line, const char * fmt, ...);

From b167e88422e769db93de12c1e8d820569fdb3fdd Mon Sep 17 00:00:00 2001
From: MCUdude <hansibull@gmail.com>
Date: Sun, 19 Jun 2022 10:53:07 +0200
Subject: [PATCH 13/33] Reduce programmer description string length  to less
 than 80 characters. #941 related

---
 src/avrdude.conf.in | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/avrdude.conf.in b/src/avrdude.conf.in
index 362b6167..ba7f4f8e 100644
--- a/src/avrdude.conf.in
+++ b/src/avrdude.conf.in
@@ -947,9 +947,10 @@ programmer
 ;
 
 # commercial version of USBtiny, using a separate VID/PID
+# https://github.com/IowaScaledEngineering/ckt-avrprogrammer
 programmer
   id    = "iseavrprog";
-  desc  = "USBtiny-based USB programmer, https://github.com/IowaScaledEngineering/ckt-avrprogrammer";
+  desc  = "USBtiny-based programmer, https://iascaled.com";
   type  = "usbtiny";
   connection_type = usb;
   usbvid     = 0x1209;

From 37026cad52f1952732b0807974149db5280cde82 Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Sun, 19 Jun 2022 19:56:56 +0200
Subject: [PATCH 14/33] PR #1000 is done now

---
 NEWS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS b/NEWS
index 4638746a..888796ca 100644
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,8 @@ Changes since version 7.0:
     - Fix .Dd macro in manpage #949
     - fix M1 homebrew path #950
     - CMake Enhancements #962
+    - Reduce programmer desc string length in avrdude.conf
+      to < 80 characters #1000
 
   * Internals:
 

From 963a1e54afee8f828e2b3f36ace79f1d55f6a5b0 Mon Sep 17 00:00:00 2001
From: MCUdude <hansibull@gmail.com>
Date: Sun, 29 May 2022 13:12:50 +0200
Subject: [PATCH 15/33] Fix JTAG transaction close issue  Fixes issue #366

---
 src/jtagmkII.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/jtagmkII.c b/src/jtagmkII.c
index fc06301c..b1024b53 100644
--- a/src/jtagmkII.c
+++ b/src/jtagmkII.c
@@ -1840,8 +1840,8 @@ void jtagmkII_close(PROGRAMMER * pgm)
 
   avrdude_message(MSG_NOTICE2, "%s: jtagmkII_close()\n", progname);
 
-  if (pgm->flag & PGM_FL_IS_PDI) {
-    /* When in PDI mode, restart target. */
+  if (pgm->flag & (PGM_FL_IS_PDI | PGM_FL_IS_JTAG)) {
+    /* When in PDI or JTAG mode, restart target. */
     buf[0] = CMND_GO;
     avrdude_message(MSG_NOTICE2, "%s: jtagmkII_close(): Sending GO command: ",
 	      progname);

From 8bd39157c199508c0d3f61b62d159d0ba271387c Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Sun, 26 Jun 2022 22:58:25 +0200
Subject: [PATCH 16/33] Closing PR 979

---
 NEWS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS b/NEWS
index 888796ca..16fef572 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,7 @@ Changes since version 7.0:
     - Fix micronucleus bootloader to check for unresponsive USB
       devices #945
     - Fix src/CMakeLists.txt to honor CMAKE_INSTALL_LIBDIR #972
+    - [bug #43898] atmega644p remains stopped after JTAG transaction #366
 
   * Pull requests:
 
@@ -26,6 +27,7 @@ Changes since version 7.0:
     - CMake Enhancements #962
     - Reduce programmer desc string length in avrdude.conf
       to < 80 characters #1000
+    - Dragon JTAG fix #979
 
   * Internals:
 

From 134509cc6fcee6c595f7ccaed21956c251647fcb Mon Sep 17 00:00:00 2001
From: prchal <jiri.prchal@aksignal.cz>
Date: Tue, 7 Jun 2022 11:50:03 +0200
Subject: [PATCH 17/33] adding support for all Linux baud rates v.2

If optiboot can work at higher bauds, why not avrdude.
Versoin 2 of #985.
Linux uses the old-style bitmapped version of the Bxxxx macros.
---
 src/ser_posix.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/src/ser_posix.c b/src/ser_posix.c
index 2c5d45b5..53d8cd15 100644
--- a/src/ser_posix.c
+++ b/src/ser_posix.c
@@ -76,6 +76,45 @@ static struct baud_mapping baud_lookup_table [] = {
 #endif
 #ifdef B230400
   { 230400, B230400 },
+#endif
+#ifdef B250000
+  { 250000, B250000 },
+#endif
+#ifdef B460800
+  { 460800, B460800 },
+#endif
+#ifdef B500000
+  { 500000, B500000 },
+#endif
+#ifdef B576000
+  { 576000, B576000 },
+#endif
+#ifdef B921600
+  { 921600, B921600 },
+#endif
+#ifdef B1000000
+  { 1000000, B1000000 },
+#endif
+#ifdef B1152000
+  { 1152000, B1152000 },
+#endif
+#ifdef B1500000
+  { 1500000, B1500000 },
+#endif
+#ifdef B2000000
+  { 2000000, B2000000 },
+#endif
+#ifdef B2500000
+  { 2500000, B2500000 },
+#endif
+#ifdef B3000000
+  { 3000000, B3000000 },
+#endif
+#ifdef B3500000
+  { 3500000, B3500000 },
+#endif
+#ifdef B4000000
+  { 4000000, B4000000 },
 #endif
   { 0,      0 }                 /* Terminator. */
 };

From ad2be990b762e92872e16d969634e252434ff71f Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Sun, 26 Jun 2022 23:00:32 +0200
Subject: [PATCH 18/33] PR 993 done

---
 NEWS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/NEWS b/NEWS
index 16fef572..da4e42d0 100644
--- a/NEWS
+++ b/NEWS
@@ -28,6 +28,7 @@ Changes since version 7.0:
     - Reduce programmer desc string length in avrdude.conf
       to < 80 characters #1000
     - Dragon JTAG fix #979
+    - adding support for all Linux baud rates v.2 #993
 
   * Internals:
 

From ef785a617ac9a79f4f438fdb87500855f2a2a9a8 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@open.ac.uk>
Date: Fri, 29 Apr 2022 00:37:28 +0100
Subject: [PATCH 19/33] Treat x bits in .conf SPI commands as 0

---
 src/avrpart.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/avrpart.c b/src/avrpart.c
index dc6def44..fdff0f78 100644
--- a/src/avrpart.c
+++ b/src/avrpart.c
@@ -82,11 +82,11 @@ int avr_set_bits(OPCODE * op, unsigned char * cmd)
   unsigned char mask;
 
   for (i=0; i<32; i++) {
-    if (op->bit[i].type == AVR_CMDBIT_VALUE) {
+    if (op->bit[i].type == AVR_CMDBIT_VALUE || op->bit[i].type == AVR_CMDBIT_IGNORE) {
       j = 3 - i / 8;
       bit = i % 8;
       mask = 1 << bit;
-      if (op->bit[i].value)
+      if (op->bit[i].value && op->bit[i].type == AVR_CMDBIT_VALUE)
         cmd[j] = cmd[j] | mask;
       else
         cmd[j] = cmd[j] & ~mask;

From 8953967fc38fc3785e4cb9eb7cf3354ebf5b8a83 Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Wed, 15 Jun 2022 23:32:22 +0200
Subject: [PATCH 20/33] Replace internal knowledge in jtag3.c by a public API

In certain situations (CRC failure, device locked), that JTAG3
read functions need to return an indication to the caller that
it is OK to proceed, and allow erasing the device anyway.

Historically, the JTAG3 code passed the respective protocol
errors directly (and unexplained) up to the caller, leaving
the decision to the caller how to handle the situation.

Replace that by a more common return value API. New code should
prefer this API instead of any hardcoded return values.
---
 src/avr.c           | 12 ++++++------
 src/jtag3.c         | 31 +++++++++++++++++++++----------
 src/jtag3_private.h |  1 +
 src/libavrdude.h    | 10 ++++++++++
 src/main.c          |  5 ++---
 5 files changed, 40 insertions(+), 19 deletions(-)

diff --git a/src/avr.c b/src/avr.c
index d6e78bb5..a8945d86 100644
--- a/src/avr.c
+++ b/src/avr.c
@@ -439,16 +439,16 @@ int avr_read(PROGRAMMER * pgm, AVRPART * p, char * memtype,
 	(vmem->tags[i] & TAG_ALLOCATED) != 0)
     {
       rc = pgm->read_byte(pgm, p, mem, i, mem->buf + i);
-      if (rc != 0) {
+      if (rc != LIBAVRDUDE_SUCCESS) {
         avrdude_message(MSG_INFO, "avr_read(): error reading address 0x%04lx\n", i);
-        if (rc == -1) {
+        if (rc == LIBAVRDUDE_GENERAL_FAILURE) {
           avrdude_message(MSG_INFO, "    read operation not supported for memory \"%s\"\n",
                           memtype);
-          return -2;
+          return LIBAVRDUDE_NOTSUPPORTED;
         }
         avrdude_message(MSG_INFO, "    read operation failed for memory \"%s\"\n",
                         memtype);
-        return rc;
+        return LIBAVRDUDE_SOFTFAIL;
       }
     }
     report_progress(i, mem->size, NULL);
@@ -1035,14 +1035,14 @@ int avr_signature(PROGRAMMER * pgm, AVRPART * p)
 
   report_progress (0,1,"Reading");
   rc = avr_read(pgm, p, "signature", 0);
-  if (rc < 0) {
+  if (rc < LIBAVRDUDE_SUCCESS) {
     avrdude_message(MSG_INFO, "%s: error reading signature data for part \"%s\", rc=%d\n",
                     progname, p->desc, rc);
     return rc;
   }
   report_progress (1,1,NULL);
 
-  return 0;
+  return LIBAVRDUDE_SUCCESS;
 }
 
 static uint8_t get_fuse_bitmask(AVRMEM * m) {
diff --git a/src/jtag3.c b/src/jtag3.c
index 6d358dfa..23df86ff 100644
--- a/src/jtag3.c
+++ b/src/jtag3.c
@@ -313,6 +313,16 @@ static void jtag3_prmsg(PROGRAMMER * pgm, unsigned char * data, size_t len)
   }
 }
 
+static int jtag3_errcode(int status)
+{
+  if (status >= LIBAVRDUDE_SUCCESS)
+    return status;
+  if (status == RSP3_FAIL_OCD_LOCKED ||
+      status == RSP3_FAIL_CRC_FAILURE)
+    return LIBAVRDUDE_SOFTFAIL;
+  return LIBAVRDUDE_GENERAL_FAILURE;
+}
+
 static void jtag3_prevent(PROGRAMMER * pgm, unsigned char * data, size_t len)
 {
   int i;
@@ -850,7 +860,7 @@ int jtag3_recv(PROGRAMMER * pgm, unsigned char **msg) {
       putc('\n', stderr);
     avrdude_message(MSG_NOTICE2, "%s: %s command: timeout/error communicating with programmer (status %d)\n",
                     progname, descr, status);
-    return -1;
+    return LIBAVRDUDE_GENERAL_FAILURE;
   } else if (verbose >= 3) {
     putc('\n', stderr);
     jtag3_prmsg(pgm, *resp, status);
@@ -871,10 +881,11 @@ int jtag3_recv(PROGRAMMER * pgm, unsigned char **msg) {
     status = (*resp)[3];
     free(*resp);
     resp = 0;
-    return -status;
+
+    return jtag3_errcode(status);
   }
 
-  return status;
+  return LIBAVRDUDE_SUCCESS;
 }
 
 
@@ -987,10 +998,10 @@ static int jtag3_program_enable(PROGRAMMER * pgm)
     free(resp);
     PDATA(pgm)->prog_enabled = 1;
 
-    return 0;
+    return LIBAVRDUDE_SUCCESS;
   }
 
-  return status;
+  return jtag3_errcode(status);
 }
 
 static int jtag3_program_disable(PROGRAMMER * pgm)
@@ -1921,7 +1932,7 @@ static int jtag3_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 
   if (!(pgm->flag & PGM_FL_IS_DW))
     if ((status = jtag3_program_enable(pgm)) < 0)
-      return status;
+      return jtag3_errcode(status);
 
   cmd[0] = SCOPE_AVR;
   cmd[1] = CMD3_READ_MEMORY;
@@ -2007,7 +2018,7 @@ static int jtag3_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 
     if (addr == 0) {
       if ((status = jtag3_command(pgm, cmd, 12, &resp, "read memory")) < 0)
-	return status;
+	return jtag3_errcode(status);
 
       signature_cache[0] = resp[4];
       signature_cache[1] = resp[5];
@@ -2057,7 +2068,7 @@ static int jtag3_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
   }
 
   if ((status = jtag3_command(pgm, cmd, 12, &resp, "read memory")) < 0)
-    return status;
+    return jtag3_errcode(status);
 
   if (resp[1] != RSP3_DATA ||
       status < (pagesize? pagesize: 1) + 4) {
@@ -2185,7 +2196,7 @@ static int jtag3_write_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
   cmd[13] = data;
 
   if ((status = jtag3_command(pgm, cmd, 14, &resp, "write memory")) < 0)
-    return status;
+    return jtag3_errcode(status);
 
   free(resp);
 
@@ -2316,7 +2327,7 @@ int jtag3_read_sib(PROGRAMMER * pgm, AVRPART * p, char * sib)
   u32_to_b4(cmd + 8, AVR_SIBLEN);
 
   if ((status = jtag3_command(pgm, cmd, 12, &resp, "read SIB")) < 0)
-	return status;
+	return jtag3_errcode(status);
 
   memcpy(sib, resp+3, AVR_SIBLEN);
   sib[AVR_SIBLEN] = 0; // Zero terminate string
diff --git a/src/jtag3_private.h b/src/jtag3_private.h
index a3e7fb08..6385aa4c 100644
--- a/src/jtag3_private.h
+++ b/src/jtag3_private.h
@@ -145,6 +145,7 @@
 #  define RSP3_FAIL_UNSUPP_MEMORY       0x34 /* unsupported memory type */
 #  define RSP3_FAIL_WRONG_LENGTH        0x35 /* wrong lenth for mem access */
 #  define RSP3_FAIL_OCD_LOCKED          0x44 /* device is locked */
+#  define RSP3_FAIL_CRC_FAILURE         0x47 /* CRC failure in device */
 #  define RSP3_FAIL_NOT_UNDERSTOOD      0x91
 
 /* ICE events */
diff --git a/src/libavrdude.h b/src/libavrdude.h
index ddb72b48..46789f4f 100644
--- a/src/libavrdude.h
+++ b/src/libavrdude.h
@@ -27,6 +27,16 @@
 #include <stdint.h>
 
 typedef uint32_t pinmask_t;
+/*
+ * Values returned by library functions.
+ * Some library functions also return a count, i.e. a positive
+ * number greater than 0.
+ */
+#define LIBAVRDUDE_SUCCESS 0
+#define LIBAVRDUDE_GENERAL_FAILURE (-1)
+#define LIBAVRDUDE_NOTSUPPORTED (-2) // operation not supported
+#define LIBAVRDUDE_SOFTFAIL (-3) // returned by avr_signature() if caller
+                                 // might proceed with chip erase
 
 /* formerly lists.h */
 
diff --git a/src/main.c b/src/main.c
index 253c6e51..5b0a6e38 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1116,9 +1116,8 @@ int main(int argc, char * argv [])
     usleep(waittime);
     if (init_ok) {
       rc = avr_signature(pgm, p);
-      if (rc != 0) {
-        // -68 == -(0x44) == -(RSP3_FAIL_OCD_LOCKED)
-        if ((rc == -68) && (p->flags & AVRPART_HAS_UPDI) && (attempt < 1)) {
+      if (rc != LIBAVRDUDE_SUCCESS) {
+        if ((rc == LIBAVRDUDE_SOFTFAIL) && (p->flags & AVRPART_HAS_UPDI) && (attempt < 1)) {
           attempt++;
           if (pgm->read_sib) {
              // Read SIB and compare FamilyID

From f22b81c00e81604596cab1ab57c89b526c9d92bc Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Wed, 22 Jun 2022 23:33:53 +0200
Subject: [PATCH 21/33] Fix a number of logic errors in the previous commits

RSP3_FAIL_CRC_FAILURE is 0x43 rather than 0x47.

jtag3_errcode() must only be applied to a reason code, not
to any general status code.
---
 src/jtag3.c         | 32 +++++++++++++++-----------------
 src/jtag3_private.h |  2 +-
 2 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/src/jtag3.c b/src/jtag3.c
index 23df86ff..4c159ee8 100644
--- a/src/jtag3.c
+++ b/src/jtag3.c
@@ -313,12 +313,10 @@ static void jtag3_prmsg(PROGRAMMER * pgm, unsigned char * data, size_t len)
   }
 }
 
-static int jtag3_errcode(int status)
+static int jtag3_errcode(int reason)
 {
-  if (status >= LIBAVRDUDE_SUCCESS)
-    return status;
-  if (status == RSP3_FAIL_OCD_LOCKED ||
-      status == RSP3_FAIL_CRC_FAILURE)
+  if (reason == RSP3_FAIL_OCD_LOCKED ||
+      reason == RSP3_FAIL_CRC_FAILURE)
     return LIBAVRDUDE_SOFTFAIL;
   return LIBAVRDUDE_GENERAL_FAILURE;
 }
@@ -844,7 +842,7 @@ int jtag3_recv(PROGRAMMER * pgm, unsigned char **msg) {
   }
 }
 
- int jtag3_command(PROGRAMMER *pgm, unsigned char *cmd, unsigned int cmdlen,
+int jtag3_command(PROGRAMMER *pgm, unsigned char *cmd, unsigned int cmdlen,
 		   unsigned char **resp, const char *descr)
 {
   int status;
@@ -868,9 +866,10 @@ int jtag3_recv(PROGRAMMER * pgm, unsigned char **msg) {
     avrdude_message(MSG_NOTICE2, "0x%02x (%d bytes msg)\n", (*resp)[1], status);
   }
 
-  c = (*resp)[1];
-  if ((c & RSP3_STATUS_MASK) != RSP3_OK) {
-    if ((c == RSP3_FAILED) && ((*resp)[3] == RSP3_FAIL_OCD_LOCKED)) {
+  c = (*resp)[1] & RSP3_STATUS_MASK;
+  if (c != RSP3_OK) {
+    if ((c == RSP3_FAILED) && ((*resp)[3] == RSP3_FAIL_OCD_LOCKED ||
+			       (*resp)[3] == RSP3_FAIL_CRC_FAILURE)) {
       avrdude_message(MSG_INFO,
 		      "%s: Device is locked! Chip erase required to unlock.\n",
 		      progname);
@@ -881,11 +880,10 @@ int jtag3_recv(PROGRAMMER * pgm, unsigned char **msg) {
     status = (*resp)[3];
     free(*resp);
     resp = 0;
-
     return jtag3_errcode(status);
   }
 
-  return LIBAVRDUDE_SUCCESS;
+  return status;
 }
 
 
@@ -1001,7 +999,7 @@ static int jtag3_program_enable(PROGRAMMER * pgm)
     return LIBAVRDUDE_SUCCESS;
   }
 
-  return jtag3_errcode(status);
+  return status;
 }
 
 static int jtag3_program_disable(PROGRAMMER * pgm)
@@ -1932,7 +1930,7 @@ static int jtag3_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 
   if (!(pgm->flag & PGM_FL_IS_DW))
     if ((status = jtag3_program_enable(pgm)) < 0)
-      return jtag3_errcode(status);
+      return status;
 
   cmd[0] = SCOPE_AVR;
   cmd[1] = CMD3_READ_MEMORY;
@@ -2018,7 +2016,7 @@ static int jtag3_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 
     if (addr == 0) {
       if ((status = jtag3_command(pgm, cmd, 12, &resp, "read memory")) < 0)
-	return jtag3_errcode(status);
+	return status;
 
       signature_cache[0] = resp[4];
       signature_cache[1] = resp[5];
@@ -2068,7 +2066,7 @@ static int jtag3_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
   }
 
   if ((status = jtag3_command(pgm, cmd, 12, &resp, "read memory")) < 0)
-    return jtag3_errcode(status);
+    return status;
 
   if (resp[1] != RSP3_DATA ||
       status < (pagesize? pagesize: 1) + 4) {
@@ -2196,7 +2194,7 @@ static int jtag3_write_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
   cmd[13] = data;
 
   if ((status = jtag3_command(pgm, cmd, 14, &resp, "write memory")) < 0)
-    return jtag3_errcode(status);
+    return status;
 
   free(resp);
 
@@ -2327,7 +2325,7 @@ int jtag3_read_sib(PROGRAMMER * pgm, AVRPART * p, char * sib)
   u32_to_b4(cmd + 8, AVR_SIBLEN);
 
   if ((status = jtag3_command(pgm, cmd, 12, &resp, "read SIB")) < 0)
-	return jtag3_errcode(status);
+	return status;
 
   memcpy(sib, resp+3, AVR_SIBLEN);
   sib[AVR_SIBLEN] = 0; // Zero terminate string
diff --git a/src/jtag3_private.h b/src/jtag3_private.h
index 6385aa4c..7d0cbb74 100644
--- a/src/jtag3_private.h
+++ b/src/jtag3_private.h
@@ -144,8 +144,8 @@
 #  define RSP3_FAIL_WRONG_MODE          0x32 /* progmode vs. non-prog */
 #  define RSP3_FAIL_UNSUPP_MEMORY       0x34 /* unsupported memory type */
 #  define RSP3_FAIL_WRONG_LENGTH        0x35 /* wrong lenth for mem access */
+#  define RSP3_FAIL_CRC_FAILURE         0x43 /* CRC failure in device */
 #  define RSP3_FAIL_OCD_LOCKED          0x44 /* device is locked */
-#  define RSP3_FAIL_CRC_FAILURE         0x47 /* CRC failure in device */
 #  define RSP3_FAIL_NOT_UNDERSTOOD      0x91
 
 /* ICE events */

From d2bb964fc74e7703a25a2256d0bf6cb0992eb4f6 Mon Sep 17 00:00:00 2001
From: MCUdude <hansibull@gmail.com>
Date: Sat, 25 Jun 2022 11:39:16 +0200
Subject: [PATCH 22/33] Attempt to fix EEPROM write issue #1009

---
 src/jtag3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/jtag3.c b/src/jtag3.c
index 4c159ee8..6a4004f3 100644
--- a/src/jtag3.c
+++ b/src/jtag3.c
@@ -1770,7 +1770,7 @@ static int jtag3_paged_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
       free(cmd);
       return n_bytes;
     }
-    cmd[3] = ( p->flags & AVRPART_HAS_PDI ) ? MTYPE_EEPROM_XMEGA : MTYPE_EEPROM_PAGE;
+    cmd[3] = ( p->flags & AVRPART_HAS_PDI || p->flags & AVRPART_HAS_UPDI ) ? MTYPE_EEPROM_XMEGA : MTYPE_EEPROM_PAGE;
     PDATA(pgm)->eeprom_pageaddr = (unsigned long)-1L;
   } else if (strcmp(m->desc, "usersig") == 0 ||
              strcmp(m->desc, "userrow") == 0) {

From bdab12d8fbdf0bc674c81edac5e34b1b9d3f7c05 Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Tue, 28 Jun 2022 22:53:24 +0200
Subject: [PATCH 23/33] PR 996 and 1013 done

---
 NEWS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS b/NEWS
index da4e42d0..d5ce1df4 100644
--- a/NEWS
+++ b/NEWS
@@ -29,6 +29,8 @@ Changes since version 7.0:
       to < 80 characters #1000
     - Dragon JTAG fix #979
     - adding support for all Linux baud rates v.2 #993
+    - Replace internal knowledge in jtag3.c by a public API #996
+    - JTAG3 UPDI EEPROM fix #1013
 
   * Internals:
 

From 2827c2695ee938735d10ea2d34c8ad69642df14b Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Tue, 28 Jun 2022 22:46:06 +0100
Subject: [PATCH 24/33] Update NEWS

---
 NEWS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/NEWS b/NEWS
index d5ce1df4..e78362b3 100644
--- a/NEWS
+++ b/NEWS
@@ -31,6 +31,7 @@ Changes since version 7.0:
     - adding support for all Linux baud rates v.2 #993
     - Replace internal knowledge in jtag3.c by a public API #996
     - JTAG3 UPDI EEPROM fix #1013
+    - Treat x bits in .conf SPI commands as 0 #943
 
   * Internals:
 

From 237cb6321116ab30f02984148758a9db633ce07e Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Mon, 4 Jul 2022 12:25:50 +0100
Subject: [PATCH 25/33] Steamline avrftdi support for ATmega2560 et al

---
 src/avrftdi.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/avrftdi.c b/src/avrftdi.c
index c6d2f86e..54490dc0 100644
--- a/src/avrftdi.c
+++ b/src/avrftdi.c
@@ -917,6 +917,10 @@ static int avrftdi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
 static int
 avrftdi_lext(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m, unsigned int address)
 {
+	/* nothing to do if load extended address command unavailable */
+        if(m->op[AVR_OP_LOAD_EXT_ADDR] == NULL)
+		return 0;
+
 	avrftdi_t *pdata = to_pdata(pgm);
 	unsigned char buf[] = { 0x00, 0x00, 0x00, 0x00 };
 
@@ -1019,7 +1023,7 @@ static int avrftdi_flash_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 	page_size = m->page_size;
 
 	/* on large-flash devices > 128k issue extended address command when needed */
-	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, addr/2) < 0)
+	if(avrftdi_lext(pgm, p, m, addr/2) < 0)
 		return -1;
 	
 	/* prepare the command stream for the whole page */
@@ -1102,7 +1106,6 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 {
 	OPCODE * readop;
 	int byte, word;
-	unsigned int address = addr/2;
 
 	unsigned int buf_size = 4 * len + 4;
 	unsigned char* o_buf = alloca(buf_size);
@@ -1122,7 +1125,7 @@ static int avrftdi_flash_read(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
 		return -1;
 	}
 	
-	if(m->op[AVR_OP_LOAD_EXT_ADDR] && avrftdi_lext(pgm, p, m, address) < 0)
+	if(avrftdi_lext(pgm, p, m, addr/2) < 0)
 		return -1;
 	
 	/* word addressing! */

From a721e485cb873c1ef38bbe756c85cc012d412327 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Mon, 4 Jul 2022 23:04:36 +0100
Subject: [PATCH 26/33] Refactor paged read/write routines in ft245r.c

---
 src/ft245r.c | 326 +++++++++++++++++++++++----------------------------
 1 file changed, 149 insertions(+), 177 deletions(-)

diff --git a/src/ft245r.c b/src/ft245r.c
index d5af4ca9..4525cab1 100644
--- a/src/ft245r.c
+++ b/src/ft245r.c
@@ -107,10 +107,10 @@ void ft245r_initpgm(PROGRAMMER * pgm) {
 
 #else
 
-#define FT245R_CYCLES	2
-#define FT245R_FRAGMENT_SIZE  512
-#define REQ_OUTSTANDINGS	10
-//#define USE_INLINE_WRITE_PAGE
+#define FT245R_CYCLES          2
+#define FT245R_CMD_SIZE       (4 * 8*FT245R_CYCLES)
+#define FT245R_FRAGMENT_SIZE  (8 * FT245R_CMD_SIZE)
+#define REQ_OUTSTANDINGS      10
 
 #define FT245R_DEBUG	0
 /*
@@ -992,40 +992,18 @@ static void ft245r_display(PROGRAMMER * pgm, const char * p) {
     pgm_display_generic_mask(pgm, p, SHOW_ALL_PINS);
 }
 
-static int ft245r_paged_write_gen(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                  unsigned int page_size, unsigned int addr,
-                                  unsigned int n_bytes) {
-    unsigned long i, pa;
-    int rc;
 
-    for (i=0; i<n_bytes; i++, addr++) {
-        rc = avr_write_byte_default(pgm, p, m, addr, m->buf[addr]);
-        if (rc != 0) {
+static int ft245r_paged_write_gen(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
+             unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
+    for(int i=0; i < (int) n_bytes; i++, addr++)
+        if(avr_write_byte_default(pgm, p, m, addr, m->buf[addr]) != 0)
             return -2;
-        }
 
-        if (m->paged) {
-            // Can this piece of code ever be activated?? Do AVRs exist that
-            // have paged non-flash memories? -- REW
-            // XXX Untested code below.
-            /*
-             * check to see if it is time to flush the page with a page
-             * write
-             */
-
-            if (((addr % m->page_size) == m->page_size-1) || (i == n_bytes-1)) {
-                pa = addr - (addr % m->page_size);
-
-                rc = avr_write_page(pgm, p, m, pa);
-                if (rc != 0) {
-                    return -2;
-                }
-            }
-        }
-    }
-    return i;
+    return n_bytes;
 }
 
+
 static struct ft245r_request {
     int addr;
     int bytes;
@@ -1081,178 +1059,172 @@ static int do_request(PROGRAMMER * pgm, AVRMEM *m) {
     return 1;
 }
 
-static int ft245r_paged_write_flash(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                    int page_size, int addr, int n_bytes) {
-    unsigned int    i,j;
-    int addr_save,buf_pos,do_page_write,req_count;
-    unsigned char buf[FT245R_FRAGMENT_SIZE+1+128];
 
-    req_count = 0;
-    for (i=0; i<n_bytes; ) {
-        addr_save = addr;
-        buf_pos = 0;
-        do_page_write = 0;
-        for (j=0; j< FT245R_FRAGMENT_SIZE/8/FT245R_CYCLES/4; j++) {
-            buf_pos += set_data(pgm, buf+buf_pos, (addr & 1)?0x48:0x40 );
-            buf_pos += set_data(pgm, buf+buf_pos, (addr >> 9) & 0xff );
-            buf_pos += set_data(pgm, buf+buf_pos, (addr >> 1) & 0xff );
-            buf_pos += set_data(pgm, buf+buf_pos, m->buf[addr]);
-            addr ++;
-            i++;
-            if ( (m->paged) &&
-                    (((i % m->page_size) == 0) || (i == n_bytes))) {
-                do_page_write = 1;
-                break;
-            }
-        }
-#if defined(USE_INLINE_WRITE_PAGE)
-        if (do_page_write) {
-            int addr_wk = addr_save - (addr_save % m->page_size);
-            /* If this device has a "load extended address" command, issue it. */
-            if (m->op[AVR_OP_LOAD_EXT_ADDR]) {
-                unsigned char cmd[4];
-                OPCODE *lext = m->op[AVR_OP_LOAD_EXT_ADDR];
+static int ft245r_paged_write_flash(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
+             unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
 
-                memset(cmd, 0, 4);
-                avr_set_bits(lext, cmd);
-                avr_set_addr(lext, cmd, addr_wk/2);
-                buf_pos += set_data(pgm, buf+buf_pos, cmd[0]);
-                buf_pos += set_data(pgm, buf+buf_pos, cmd[1]);
-                buf_pos += set_data(pgm, buf+buf_pos, cmd[2]);
-                buf_pos += set_data(pgm, buf+buf_pos, cmd[3]);
+    int i, j, addr_save, buf_pos, req_count, do_page_write;
+    unsigned char buf[FT245R_FRAGMENT_SIZE+1];
+    unsigned char cmd[4];
+
+    if(m->op[AVR_OP_LOADPAGE_LO] == NULL || m->op[AVR_OP_LOADPAGE_HI] == NULL) {
+        avrdude_message(MSG_INFO, "AVR_OP_LOADPAGE_HI/LO command not defined for %s\n", p->desc);
+        return -1;
+    }
+
+    do_page_write = req_count = i = j = buf_pos = 0;
+    addr_save = addr;
+    while(i < (int) n_bytes) {
+        int spi = addr&1? AVR_OP_LOADPAGE_HI: AVR_OP_LOADPAGE_LO;
+
+        // put the SPI loadpage command as FT245R_CMD_SIZE bytes into buffer
+        memset(cmd, 0, sizeof cmd);
+        avr_set_bits(m->op[spi], cmd);
+        avr_set_addr(m->op[spi], cmd, addr/2);
+        avr_set_input(m->op[spi], cmd, m->buf[addr]);
+        for(int k=0; k<sizeof cmd; k++)
+           buf_pos += set_data(pgm, buf+buf_pos, cmd[k]);
+
+        i++; j++; addr++;
+
+        if(m->paged && (i%m->page_size == 0 || i >= (int) n_bytes))
+            do_page_write = 1;
+
+        // page boundary, finished or buffer exhausted? queue up requests
+        if(do_page_write || i >= (int) n_bytes || j >= FT245R_FRAGMENT_SIZE/FT245R_CMD_SIZE) {
+            if(i >= n_bytes) {
+                ft245r_out = SET_BITS_0(ft245r_out, pgm, PIN_AVR_SCK, 0); // SCK down
+                buf[buf_pos++] = ft245r_out;
+            } else {
+                // stretch sequence to allow correct readout, see extract_data()
+                buf[buf_pos] = buf[buf_pos - 1];
+                buf_pos++;
             }
-            buf_pos += set_data(pgm, buf+buf_pos, 0x4C); /* Issue Page Write */
-            buf_pos += set_data(pgm, buf+buf_pos,(addr_wk >> 9) & 0xff);
-            buf_pos += set_data(pgm, buf+buf_pos,(addr_wk >> 1) & 0xff);
-            buf_pos += set_data(pgm, buf+buf_pos, 0);
-        }
-#endif
-        if (i >= n_bytes) {
-            ft245r_out = SET_BITS_0(ft245r_out,pgm,PIN_AVR_SCK,0); // sck down
-            buf[buf_pos++] = ft245r_out;
-        }
-        else {
-            /* stretch sequence to allow correct readout, see extract_data() */
-            buf[buf_pos] = buf[buf_pos - 1];
-            buf_pos++;
-        }
-        ft245r_send(pgm, buf, buf_pos);
-        put_request(addr_save, buf_pos, 0);
-        //ft245r_sync(pgm);
-#if 0
-        avrdude_message(MSG_INFO, "send addr 0x%04x bufsize %d [%02x %02x] page_write %d\n",
-                addr_save,buf_pos,
-                extract_data_out(pgm, buf , (0*4 + 3) ),
-                extract_data_out(pgm, buf , (1*4 + 3) ),
-                do_page_write);
-#endif
-        req_count++;
-        if (req_count > REQ_OUTSTANDINGS)
-            do_request(pgm, m);
-        if (do_page_write) {
-#if defined(USE_INLINE_WRITE_PAGE)
-            while (do_request(pgm, m))
-                ;
-            ft245r_usleep(pgm, m->max_write_delay);
-#else
-            int addr_wk = addr_save - (addr_save % m->page_size);
-            int rc;
-            while (do_request(pgm, m))
-                ;
-            rc = avr_write_page(pgm, p, m, addr_wk);
-            if (rc != 0) {
-                return -2;
+            ft245r_send(pgm, buf, buf_pos);
+            put_request(addr_save, buf_pos, 0);
+
+            if(++req_count > REQ_OUTSTANDINGS)
+                do_request(pgm, m);
+
+            if(do_page_write) {
+                while(do_request(pgm, m))
+                    continue;
+                if(avr_write_page(pgm, p, m, addr_save - (addr_save % m->page_size)) != 0)
+                    return -2;
+                do_page_write = req_count = 0;
             }
-#endif
-            req_count = 0;
+
+            // reset buffer variables
+            j = buf_pos = 0;
+            addr_save = addr;
         }
     }
-    while (do_request(pgm, m))
-        ;
-    return i;
+
+    while(do_request(pgm, m))
+        continue;
+
+    return n_bytes;
 }
 
 
 static int ft245r_paged_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                              unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
-    if (strcmp(m->desc, "flash") == 0) {
+            unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
+    if(!n_bytes)
+        return 0;
+
+    if(strcmp(m->desc, "flash") == 0)
         return ft245r_paged_write_flash(pgm, p, m, page_size, addr, n_bytes);
-    } else if (strcmp(m->desc, "eeprom") == 0) {
+
+    if(strcmp(m->desc, "eeprom") == 0)
         return ft245r_paged_write_gen(pgm, p, m, page_size, addr, n_bytes);
-    } else {
-        return -2;
-    }
+
+    return -2;
 }
 
-static int ft245r_paged_load_gen(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                 unsigned int page_size, unsigned int addr,
-                                 int n_bytes) {
-    unsigned char    rbyte;
-    unsigned long    i;
-    int rc;
+static int ft245r_paged_load_gen(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
+             unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
 
-    for (i=0; i<n_bytes; i++) {
-        rc = avr_read_byte_default(pgm, p, m, i+addr, &rbyte);
-        if (rc != 0) {
+    for(int i=0; i < (int) n_bytes; i++) {
+        unsigned char rbyte;
+
+        if(avr_read_byte_default(pgm, p, m, addr+i, &rbyte) != 0)
             return -2;
-        }
-        m->buf[i+addr] = rbyte;
+
+        m->buf[addr+i] = rbyte;
     }
+
     return 0;
 }
 
-static int ft245r_paged_load_flash(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                   unsigned int page_size, unsigned int addr,
-                                   unsigned int n_bytes) {
-    unsigned long    i,j,n;
-    int addr_save,buf_pos;
-    int req_count = 0;
+
+static int ft245r_paged_load_flash(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
+            unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
+    int i, j, addr_save, buf_pos, req_count;
     unsigned char buf[FT245R_FRAGMENT_SIZE+1];
+    unsigned char cmd[4];
 
-    for (i=0; i<n_bytes; ) {
-        buf_pos = 0;
-        addr_save = addr;
-        for (j=0; j< FT245R_FRAGMENT_SIZE/8/FT245R_CYCLES/4; j++) {
-            if (i >= n_bytes) break;
-            buf_pos += set_data(pgm, buf+buf_pos, (addr & 1)?0x28:0x20 );
-            buf_pos += set_data(pgm, buf+buf_pos, (addr >> 9) & 0xff );
-            buf_pos += set_data(pgm, buf+buf_pos, (addr >> 1) & 0xff );
-            buf_pos += set_data(pgm, buf+buf_pos, 0);
-            addr ++;
-            i++;
-        }
-        if (i >= n_bytes) {
-            ft245r_out = SET_BITS_0(ft245r_out,pgm,PIN_AVR_SCK,0); // sck down
-            buf[buf_pos++] = ft245r_out;
-        }
-        else {
-            /* stretch sequence to allow correct readout, see extract_data() */
-            buf[buf_pos] = buf[buf_pos - 1];
-            buf_pos++;
-        }
-        n = j;
-        ft245r_send(pgm, buf, buf_pos);
-        put_request(addr_save, buf_pos, n);
-        req_count++;
-        if (req_count > REQ_OUTSTANDINGS)
-            do_request(pgm, m);
-
+    if(m->op[AVR_OP_READ_LO] == NULL || m->op[AVR_OP_READ_HI] == NULL) {
+        avrdude_message(MSG_INFO, "AVR_OP_READ_HI/LO command not defined for %s\n", p->desc);
+        return -1;
     }
-    while (do_request(pgm, m))
-        ;
+
+    req_count = i = j = buf_pos = 0;
+    addr_save = addr;
+    while(i < (int) n_bytes) {
+        int spi = addr&1? AVR_OP_READ_HI: AVR_OP_READ_LO;
+
+        // put the SPI read command as FT245R_CMD_SIZE bytes into buffer
+        memset(cmd, 0, sizeof cmd);
+        avr_set_bits(m->op[spi], cmd);
+        avr_set_addr(m->op[spi], cmd, addr/2);
+        for(int k=0; k<sizeof cmd; k++)
+           buf_pos += set_data(pgm, buf+buf_pos, cmd[k]);
+
+        i++; j++; addr++;
+
+        // finished or buffer exhausted? queue up requests
+        if(i >= (int) n_bytes || j >= FT245R_FRAGMENT_SIZE/FT245R_CMD_SIZE) {
+            if(i >= (int) n_bytes) {
+                ft245r_out = SET_BITS_0(ft245r_out, pgm, PIN_AVR_SCK, 0); // SCK down
+                buf[buf_pos++] = ft245r_out;
+            } else {
+                // stretch sequence to allow correct readout, see extract_data()
+                buf[buf_pos] = buf[buf_pos - 1];
+                buf_pos++;
+            }
+            ft245r_send(pgm, buf, buf_pos);
+            put_request(addr_save, buf_pos, j);
+
+            if(++req_count > REQ_OUTSTANDINGS)
+                do_request(pgm, m);
+
+            // reset buffer variables
+            j = buf_pos = 0;
+            addr_save = addr;
+        }
+    }
+
+    while(do_request(pgm, m))
+        continue;
+
     return 0;
 }
 
-static int ft245r_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                             unsigned int page_size, unsigned int addr,
-                             unsigned int n_bytes) {
-    if (strcmp(m->desc, "flash") == 0) {
+static int ft245r_paged_load(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
+             unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
+    if(!n_bytes)
+        return 0;
+
+    if(strcmp(m->desc, "flash") == 0)
         return ft245r_paged_load_flash(pgm, p, m, page_size, addr, n_bytes);
-    } else if (strcmp(m->desc, "eeprom") == 0) {
+
+   if(strcmp(m->desc, "eeprom") == 0)
         return ft245r_paged_load_gen(pgm, p, m, page_size, addr, n_bytes);
-    } else {
-        return -2;
-    }
+
+   return -2;
 }
 
 void ft245r_initpgm(PROGRAMMER * pgm) {

From 7aad03cbcdd762b912f9ef920c2badd2463efabb Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Mon, 4 Jul 2022 23:11:32 +0100
Subject: [PATCH 27/33] Fix paged read for ATmega2560 et al for ft245r.c

---
 src/ft245r.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/ft245r.c b/src/ft245r.c
index 4525cab1..874167ac 100644
--- a/src/ft245r.c
+++ b/src/ft245r.c
@@ -1170,6 +1170,19 @@ static int ft245r_paged_load_flash(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m,
         return -1;
     }
 
+    // always called with addr at page boundary, and n_bytes == m->page_size;
+    // hence, OK to prepend load extended address command (at most) once
+    if(m->op[AVR_OP_LOAD_EXT_ADDR]) {
+        memset(cmd, 0, sizeof cmd);
+	avr_set_bits(m->op[AVR_OP_LOAD_EXT_ADDR], cmd);
+	avr_set_addr(m->op[AVR_OP_LOAD_EXT_ADDR], cmd, addr/2);
+
+        buf_pos = 0;
+        for(int k=0; k<sizeof cmd; k++)
+            buf_pos += set_data(pgm, buf+buf_pos, cmd[k]);
+        ft245r_send_and_discard(pgm, buf, buf_pos);
+    }
+
     req_count = i = j = buf_pos = 0;
     addr_save = addr;
     while(i < (int) n_bytes) {

From 2b6ee8f4d1e26699792693dd4cf97c67f9ae4431 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Mon, 4 Jul 2022 23:54:02 +0100
Subject: [PATCH 28/33] Adapt whitespace to existing style in avrftdi.c

---
 src/avrftdi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/avrftdi.c b/src/avrftdi.c
index 54490dc0..f0c07a6a 100644
--- a/src/avrftdi.c
+++ b/src/avrftdi.c
@@ -918,7 +918,7 @@ static int
 avrftdi_lext(PROGRAMMER *pgm, AVRPART *p, AVRMEM *m, unsigned int address)
 {
 	/* nothing to do if load extended address command unavailable */
-        if(m->op[AVR_OP_LOAD_EXT_ADDR] == NULL)
+	if(m->op[AVR_OP_LOAD_EXT_ADDR] == NULL)
 		return 0;
 
 	avrftdi_t *pdata = to_pdata(pgm);

From 9742c7b97aa78bb0e96435f7c4ac39e627bbd2c4 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Tue, 5 Jul 2022 00:55:58 +0100
Subject: [PATCH 29/33] Add #474 and #976 to NEWS

---
 NEWS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS b/NEWS
index e78362b3..78f59f95 100644
--- a/NEWS
+++ b/NEWS
@@ -32,6 +32,8 @@ Changes since version 7.0:
     - Replace internal knowledge in jtag3.c by a public API #996
     - JTAG3 UPDI EEPROM fix #1013
     - Treat x bits in .conf SPI commands as 0 #943
+    - Fix avrftdi support for ATmega2560 et al #474
+    - Fix avrdude.conf timings for ATmega328PB and other parts #976
 
   * Internals:
 

From d3b22fa3c620c0f8dad856214b4a5cccd0c3baff Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Tue, 5 Jul 2022 00:57:40 +0100
Subject: [PATCH 30/33] Update debug message in avr.c with correct function
 name

---
 src/avr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/avr.c b/src/avr.c
index a8945d86..7f267622 100644
--- a/src/avr.c
+++ b/src/avr.c
@@ -234,7 +234,7 @@ int avr_read_byte_default(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 
   if (readop == NULL) {
 #if DEBUG
-    avrdude_message(MSG_INFO, "avr_read_byte(): operation not supported on memory type \"%s\"\n",
+    avrdude_message(MSG_INFO, "avr_read_byte_default(): operation not supported on memory type \"%s\"\n",
                     mem->desc);
 #endif
     return -1;

From 64ee4858fd5e4a2ce65cf3c280274674c4320de5 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Tue, 5 Jul 2022 01:00:45 +0100
Subject: [PATCH 31/33] Update 2nd debug message in avr.c with correct function
 name

---
 src/avr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/avr.c b/src/avr.c
index 7f267622..17f85f34 100644
--- a/src/avr.c
+++ b/src/avr.c
@@ -650,7 +650,7 @@ int avr_write_byte_default(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 
   if (writeop == NULL) {
 #if DEBUG
-    avrdude_message(MSG_INFO, "avr_write_byte(): write not supported for memory type \"%s\"\n",
+    avrdude_message(MSG_INFO, "avr_write_byte_default(): write not supported for memory type \"%s\"\n",
                     mem->desc);
 #endif
     return -1;

From ff8f519a34ed4e167be442ca4abeac6f11cccdca Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Sun, 10 Jul 2022 23:25:31 +0100
Subject: [PATCH 32/33] Fix PICKit2 ATmega2560 flash paged flash read

The paged read in pickit2.c has two errors:
  - It drops load extended address commands unless a paged read happens at a
    64k byte boundary; this is invalid when reading files with holes
  - It wrongly assumed that flash memory is byte addressed

The fix is to carry out a load extended address command, if needed, at the
beginning of each paged flash read with the correct word address. Although the
pickit2_paged_load() has independent parameters page_size, addr and n_bytes,
AVRDUDE only ever calls paged read/write functions with page_size and n_bytes
both set to mem->page_size and addr aligned with a page boundary. Therefore, it
is sufficient to set the load extended address at the beginning of each page
read.
---
 src/pickit2.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/src/pickit2.c b/src/pickit2.c
index 9e4be94c..ac3781f5 100644
--- a/src/pickit2.c
+++ b/src/pickit2.c
@@ -491,18 +491,15 @@ static int  pickit2_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
 
     pgm->pgm_led(pgm, ON);
 
+    if (lext) {
+       memset(cmd, 0, sizeof(cmd));
+       avr_set_bits(lext, cmd);
+       avr_set_addr(lext, cmd, addr/2);
+       pgm->cmd(pgm, cmd, res);
+    }
+
     for (addr_base = addr; addr_base < max_addr; )
     {
-        if ((addr_base == 0 || (addr_base % /*ext_address_boundary*/ 65536) == 0)
-                && lext != NULL)
-        {
-            memset(cmd, 0, sizeof(cmd));
-
-            avr_set_bits(lext, cmd);
-            avr_set_addr(lext, cmd, addr_base);
-            pgm->cmd(pgm, cmd, res);
-        }
-
         // bytes to send in the next packet -- not necessary as pickit2_spi() handles breaking up
         // the data into packets -- but we need to keep transfers frequent so that we can update the
         // status indicator bar

From c81f52ff1088310e77f74d11fa8ff4238ec4a7bc Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Tue, 12 Jul 2022 15:52:37 +0100
Subject: [PATCH 33/33] Update NEWS

---
 NEWS | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 78f59f95..7bea2bcb 100644
--- a/NEWS
+++ b/NEWS
@@ -32,8 +32,12 @@ Changes since version 7.0:
     - Replace internal knowledge in jtag3.c by a public API #996
     - JTAG3 UPDI EEPROM fix #1013
     - Treat x bits in .conf SPI commands as 0 #943
-    - Fix avrftdi support for ATmega2560 et al #474
-    - Fix avrdude.conf timings for ATmega328PB and other parts #976
+    - Fix avrftdi support for ATmega2560 et al #998
+    - Fix avrdude.conf timings for ATmega328PB and other parts #1001
+    - Fix PICKit2 ATmega2560 flash paged flash read #1023
+    - Fix ft245r paged read for ATmega2560 et al #1018
+    - Add option -A that supresses trailing 0xff optimisation
+      and automatically do so for -c arduino #936
 
   * Internals: