diff --git a/swtp6800/common/bootrom.c b/swtp6800/common/bootrom.c
index f0a78b00..50965d9e 100644
--- a/swtp6800/common/bootrom.c
+++ b/swtp6800/common/bootrom.c
@@ -48,7 +48,9 @@
 #include "swtp_defs.h"
 
 
+#if !defined(DONT_USE_INTERNAL_ROM)
 #include "swtp_swtbugv10_bin.h"
+#endif /* DONT_USE_INTERNAL_ROM */
 
 #define UNIT_V_MSIZE    (UNIT_V_UF)     /* ROM Size */
 #define UNIT_MSIZE      (0x7 << UNIT_V_MSIZE)
@@ -61,7 +63,6 @@
 
 /* function prototypes */
 
-t_stat  BOOTROM_svc (UNIT *uptr);
 t_stat  BOOTROM_config (UNIT *uptr, int32 val, CONST char *cptr, void *desc);
 t_stat  BOOTROM_attach (UNIT *uptr, CONST char *cptr);
 t_stat  BOOTROM_reset (DEVICE *dptr);
diff --git a/swtp6800/common/m6800.c b/swtp6800/common/m6800.c
index df755638..35346d0f 100644
--- a/swtp6800/common/m6800.c
+++ b/swtp6800/common/m6800.c
@@ -145,13 +145,11 @@ static const char* m6800_desc(DEVICE *dptr) {
 }
 
 /* function prototypes */
-
 t_stat cpu_set_hist (UNIT *uptr, int32 val, CONST char *cptr, void *desc);
 t_stat cpu_show_hist (FILE *st, UNIT *uptr, int32 val, CONST void *desc);
 t_stat m6800_reset (DEVICE *dptr);
 t_stat m6800_ex(t_value *vptr, t_addr addr, UNIT *uptr, int32 sw);
 t_stat m6800_dep(t_value val, t_addr addr, UNIT *uptr, int32 sw);
-
 void dump_regs(void);
 int32 fetch_byte(void);
 int32 fetch_word(void);
@@ -171,12 +169,12 @@ void condevalVs(int32 op1, int32 op2);
 void condevalHa(int32 op1, int32 op2);
 
 /* external routines */
-
 extern void CPU_BD_put_mbyte(int32 addr, int32 val);
 extern void CPU_BD_put_mword(int32 addr, int32 val);
 extern int32 CPU_BD_get_mbyte(int32 addr);
 extern int32 CPU_BD_get_mword(int32 addr);
 
+//disassembly opcode table
 static const char *opcode[] = {
 "???  ", "NOP  ", "???  ", "???  ",     //0x00
 "???  ", "???  ", "TAP  ", "TPA  ",
@@ -244,6 +242,7 @@ static const char *opcode[] = {
 "???  ", "???  ", "LDX  ", "STX  ",
 };
 
+//disassembly opcode length table
 int32 oplen[256] = {
 0,1,0,0,0,0,1,1,1,1,1,1,1,1,1,1,        //0x00
 1,1,0,0,0,0,1,1,0,1,0,1,0,0,0,0,
diff --git a/swtp6800/swtp6800/swtp6800mp-a.ini b/swtp6800/swtp6800/swtp6800mp-a.ini
index 7b775df0..66ee30eb 100644
--- a/swtp6800/swtp6800/swtp6800mp-a.ini
+++ b/swtp6800/swtp6800/swtp6800mp-a.ini
@@ -3,6 +3,7 @@ attach bootrom swtbug.bin
 set cpu hex
 set cpu itrap
 set cpu mtrap
-reset
+set cpu history
 set mp-b2 bd0, bd1, bd2, bd3, bd4, bd5
+reset
 g
diff --git a/swtp6800/swtp6800/swtp6800mp-a2.ini b/swtp6800/swtp6800/swtp6800mp-a2.ini
index 5f26385a..40eb24de 100644
--- a/swtp6800/swtp6800/swtp6800mp-a2.ini
+++ b/swtp6800/swtp6800/swtp6800mp-a2.ini
@@ -4,6 +4,7 @@ set mp-a2 mon, lo_prom
 set cpu hex
 set cpu itrap
 set cpu mtrap
-reset
+set cpu history
 set mp-b2 bd0, bd1, bd2, bd3, bd4, bd5
+reset
 g
diff --git a/swtp6800/swtp6800/swtp_defs.h b/swtp6800/swtp6800/swtp_defs.h
index ae8f503f..b5309bee 100644
--- a/swtp6800/swtp6800/swtp_defs.h
+++ b/swtp6800/swtp6800/swtp_defs.h
@@ -46,8 +46,6 @@ Copyright (c) 2005-2012, William Beech
 #define DEBUG_flow      0x0001
 #define DEBUG_read      0x0002
 #define DEBUG_write     0x0004
-#define DEBUG_reg       0x0008
-#define DEBUG_asm       0x0010
 #define DEBUG_all       0xFFFF
 
 /* Simulator stop codes */