diff --git a/ChangeLog b/ChangeLog
index 53281b49..5e04ca7a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2008-10-31  Joerg Wunsch <j.gnu@uriah.heep.sax.de>
+
+	* jtagmkII.c: Fix a serious memory corruption that happened when
+	using the JTAG ICE mkII (or AVR Dragon) in ISP mode.  The wrong
+	set of per-programmer private data had been allocated (stk500v2
+	vs. jtagmkII) which was too small to hold the actual data.
+	* jtagmkII.h: (Ditto.)
+	* stk500v2.c: (Ditto.)
+
 2008-07-29  Joerg Wunsch <j.gnu@uriah.heep.sax.de>
 
 	* jtagmkII.c: Implement Xmega JTAG support.
diff --git a/jtagmkII.c b/jtagmkII.c
index 13f5e3ff..44086bfc 100644
--- a/jtagmkII.c
+++ b/jtagmkII.c
@@ -130,7 +130,7 @@ static int jtagmkII_setparm(PROGRAMMER * pgm, unsigned char parm,
 			    unsigned char * value);
 static void jtagmkII_print_parms1(PROGRAMMER * pgm, const char * p);
 
-static void jtagmkII_setup(PROGRAMMER * pgm)
+void jtagmkII_setup(PROGRAMMER * pgm)
 {
   if ((pgm->cookie = malloc(sizeof(struct pdata))) == 0) {
     fprintf(stderr,
@@ -141,7 +141,7 @@ static void jtagmkII_setup(PROGRAMMER * pgm)
   memset(pgm->cookie, 0, sizeof(struct pdata));
 }
 
-static void jtagmkII_teardown(PROGRAMMER * pgm)
+void jtagmkII_teardown(PROGRAMMER * pgm)
 {
   free(pgm->cookie);
 }
diff --git a/jtagmkII.h b/jtagmkII.h
index 9bdbae5d..32f520dd 100644
--- a/jtagmkII.h
+++ b/jtagmkII.h
@@ -38,6 +38,14 @@ void jtagmkII_dw_initpgm (PROGRAMMER * pgm);
 void jtagmkII_dragon_initpgm (PROGRAMMER * pgm);
 void jtagmkII_dragon_dw_initpgm (PROGRAMMER * pgm);
 
+/*
+ * These functions are referenced from stk500v2.c for JTAG ICE mkII
+ * and AVR Dragon programmers running in one of the STK500v2
+ * modi.
+ */
+void jtagmkII_setup(PROGRAMMER * pgm);
+void jtagmkII_teardown(PROGRAMMER * pgm);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/stk500v2.c b/stk500v2.c
index d2ef6473..5d598bf0 100644
--- a/stk500v2.c
+++ b/stk500v2.c
@@ -3482,8 +3482,8 @@ void stk500v2_jtagmkII_initpgm(PROGRAMMER * pgm)
   pgm->print_parms    = stk500v2_print_parms;
   pgm->set_sck_period = stk500v2_set_sck_period_mk2;
   pgm->perform_osccal = stk500v2_perform_osccal;
-  pgm->setup          = stk500v2_setup;
-  pgm->teardown       = stk500v2_teardown;
+  pgm->setup          = jtagmkII_setup;
+  pgm->teardown       = jtagmkII_teardown;
   pgm->page_size      = 256;
 }
 
@@ -3513,8 +3513,8 @@ void stk500v2_dragon_isp_initpgm(PROGRAMMER * pgm)
   pgm->paged_load     = stk500v2_paged_load;
   pgm->print_parms    = stk500v2_print_parms;
   pgm->set_sck_period = stk500v2_set_sck_period_mk2;
-  pgm->setup          = stk500v2_setup;
-  pgm->teardown       = stk500v2_teardown;
+  pgm->setup          = jtagmkII_setup;
+  pgm->teardown       = jtagmkII_teardown;
   pgm->page_size      = 256;
 }
 
@@ -3546,8 +3546,8 @@ void stk500v2_dragon_pp_initpgm(PROGRAMMER * pgm)
   pgm->set_varef      = stk500v2_set_varef;
   pgm->set_fosc       = stk500v2_set_fosc;
   pgm->set_sck_period = stk500v2_set_sck_period_mk2;
-  pgm->setup          = stk500v2_setup;
-  pgm->teardown       = stk500v2_teardown;
+  pgm->setup          = jtagmkII_setup;
+  pgm->teardown       = jtagmkII_teardown;
   pgm->page_size      = 256;
 }
 
@@ -3579,8 +3579,8 @@ void stk500v2_dragon_hvsp_initpgm(PROGRAMMER * pgm)
   pgm->set_varef      = stk500v2_set_varef;
   pgm->set_fosc       = stk500v2_set_fosc;
   pgm->set_sck_period = stk500v2_set_sck_period_mk2;
-  pgm->setup          = stk500v2_setup;
-  pgm->teardown       = stk500v2_teardown;
+  pgm->setup          = jtagmkII_setup;
+  pgm->teardown       = jtagmkII_teardown;
   pgm->page_size      = 256;
 }