From a536a01ebfe5f8d34c9d0abc7364d260962b4aab Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Wed, 31 Aug 2022 18:15:35 +0100
Subject: [PATCH 1/2] Create a bespoke bootloader programmer for gammaBoot
 trinkets

---
 src/avrdude.conf.in | 17 +++++++++++++++++
 src/usbtiny.c       |  8 +++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/avrdude.conf.in b/src/avrdude.conf.in
index 1152af77..f2d0c009 100644
--- a/src/avrdude.conf.in
+++ b/src/avrdude.conf.in
@@ -1458,6 +1458,23 @@ programmer
     usbpid                 = 0x0c9f;
 ;
 
+#------------------------------------------------------------
+# gemmaBoot
+#------------------------------------------------------------
+
+# Serving the Gemma bootloader
+# https://github.com/adafruit/Adafruit-Trinket-Gemma-Bootloader
+
+programmer
+    id                     = "gemmaBoot";
+    desc                   = "Gemma bootloader disguised as USBtiny";
+    type                   = "usbtiny";
+    prog_modes             = PM_SPM;
+    connection_type        = usb;
+    usbvid                 = 0x2341;
+    usbpid                 = 0x0105;
+;
+
 #------------------------------------------------------------
 # arduinoisp
 #------------------------------------------------------------
diff --git a/src/usbtiny.c b/src/usbtiny.c
index 2e319318..7153ede9 100644
--- a/src/usbtiny.c
+++ b/src/usbtiny.c
@@ -618,7 +618,13 @@ static int usbtiny_chip_erase(const PROGRAMMER *pgm, const AVRPART *p) {
   if (! usbtiny_avr_op( pgm, p, AVR_OP_CHIP_ERASE, res )) {
     return -1;
   }
-  usleep( p->chip_erase_delay );
+
+  if(pgm->prog_modes & PM_SPM) { // Talking to bootloader directly
+    AVRMEM *fl = avr_locate_mem(p, "flash");
+    // Estimated time it takes to erase all pages in bootloader
+    usleep(p->chip_erase_delay * (fl? fl->num_pages: 999));
+  } else
+    usleep(p->chip_erase_delay);
 
   // prepare for further instruction
   pgm->initialize(pgm, p);

From a5f3885b50c34799927037c2a4bb263f27c787bc Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Wed, 7 Sep 2022 09:56:28 +0100
Subject: [PATCH 2/2] Add and modify programmers for gemmaBoot in
 avrdude.conf.in

---
 src/avrdude.conf.in | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/avrdude.conf.in b/src/avrdude.conf.in
index f2d0c009..6e9df324 100644
--- a/src/avrdude.conf.in
+++ b/src/avrdude.conf.in
@@ -1459,20 +1459,35 @@ programmer
 ;
 
 #------------------------------------------------------------
-# gemmaBoot
+# arduino_gemma
 #------------------------------------------------------------
 
-# Serving the Gemma bootloader
-# https://github.com/adafruit/Adafruit-Trinket-Gemma-Bootloader
+# https://github.com/arduino/ArduinoCore-avr/tree/master/bootloaders/gemma
 
 programmer
-    id                     = "gemmaBoot";
-    desc                   = "Gemma bootloader disguised as USBtiny";
+    id                     = "arduino_gemma";
+    desc                   = "Arduino Gemma bootloader disguised as USBtiny";
     type                   = "usbtiny";
     prog_modes             = PM_SPM;
     connection_type        = usb;
     usbvid                 = 0x2341;
-    usbpid                 = 0x0105;
+    usbpid                 = 0x0c9f;
+;
+
+#------------------------------------------------------------
+# adafruit_gemma
+#------------------------------------------------------------
+
+# https://github.com/adafruit/Adafruit-Trinket-Gemma-Bootloader
+
+programmer
+    id                     = "adafruit_gemma";
+    desc                   = "Adafruit Trinket Gemma bootloader disguised as USBtiny";
+    type                   = "usbtiny";
+    prog_modes             = PM_SPM;
+    connection_type        = usb;
+    usbvid                 = 0x1781;
+    usbpid                 = 0x0c9f;
 ;
 
 #------------------------------------------------------------