diff --git a/src/emu/debug/debugcmd.c b/src/emu/debug/debugcmd.c
index 7687caea6f9..56c2404ad18 100644
--- a/src/emu/debug/debugcmd.c
+++ b/src/emu/debug/debugcmd.c
@@ -41,6 +41,7 @@ struct _global_entry
 	UINT32		size;
 };
 
+
 typedef struct _cheat_map cheat_map;
 struct _cheat_map
 {
@@ -51,19 +52,31 @@ struct _cheat_map
 	UINT8		undo:7;
 };
 
+
 typedef struct _cheat_system cheat_system;
 struct _cheat_system
 {
-	char			cpu;
-	UINT64			length;
-	UINT8			width;
-	cheat_map *		cheatmap;
-	UINT8			undo;
-	UINT8			signed_cheat;
-	UINT8			swapped_cheat;
+	char		cpu;
+	UINT64		length;
+	UINT8		width;
+	cheat_map *	cheatmap;
+	UINT8		undo;
+	UINT8		signed_cheat;
+	UINT8		swapped_cheat;
 };
 
 
+typedef struct _cheat_region_map cheat_region_map;
+struct _cheat_region_map
+{
+	UINT64		offset;
+	UINT64		endoffset;
+	UINT8		share;
+	UINT8		disabled;
+};
+
+
+
 /***************************************************************************
     GLOBAL VARIABLES
 ***************************************************************************/
@@ -1708,10 +1721,14 @@ static void execute_dump(running_machine *machine, int ref, int params, const ch
 
 static void execute_cheatinit(running_machine *machine, int ref, int params, const char *param[])
 {
-	UINT64 offset, endoffset, length = 0, real_length = 0;
+	UINT64 offset, length = 0, real_length = 0;
 	const address_space *space;
 	UINT32 active_cheat = 0;
 	UINT64 curaddr;
+	UINT8 i, region_count = 0;
+
+	address_map_entry *entry;
+	cheat_region_map cheat_region[100];
 
 	/* validate parameters */
 	if (!debug_command_parameter_cpu_space(machine, (params > 3) ? param[3] : NULL, ADDRESS_SPACE_PROGRAM, &space))
@@ -1719,6 +1736,9 @@ static void execute_cheatinit(running_machine *machine, int ref, int params, con
 
 	if (ref == 0)
 	{
+		cheat.width = 1;
+		cheat.signed_cheat = FALSE;
+		cheat.swapped_cheat = FALSE;
 		if (params > 0)
 		{
 			char *srtpnt = (char*)param[0];
@@ -1752,35 +1772,51 @@ static void execute_cheatinit(running_machine *machine, int ref, int params, con
 			else
 				cheat.swapped_cheat = FALSE;
 		}
-		else
-		{
-			cheat.width = 1;
-			cheat.signed_cheat = FALSE;
-			cheat.swapped_cheat = FALSE;
-		}
 	}
 
-	if (params > 1)
+	/* initialize entire memory by default */
+	if (params <= 1)
 	{
+		offset = 0;
+		length = space->bytemask + 1;
+		for (entry = space->map->entrylist; entry != NULL; entry = entry->next)
+		{
+			cheat_region[region_count].offset = memory_address_to_byte(space, entry->addrstart) & space->bytemask;
+			cheat_region[region_count].endoffset = memory_address_to_byte(space, entry->addrend) & space->bytemask;
+			cheat_region[region_count].share = entry->share;
+			cheat_region[region_count].disabled = (entry->write.shandler8 == SMH_RAM) ? FALSE : TRUE;
+
+			/* disable double share regions */
+			if (entry->share != 0)
+				for (i = 0; i < region_count; i++)
+					if (cheat_region[i].share == entry->share)
+						cheat_region[region_count].disabled = TRUE;
+
+			region_count++;
+		}
+	}
+	else
+	{
+		/* validate parameters */
 		if (!debug_command_parameter_number(machine, param[(ref == 0) ? 1 : 0], &offset))
 			return;
 		if (!debug_command_parameter_number(machine, param[(ref == 0) ? 2 : 1], &length))
 			return;
-	}
-	else
-	{
-		/* initialize entire memory  */
-		offset = 0;
-		length = space->bytemask + 1;
+
+		/* force region to the specified range */
+		cheat_region[region_count].offset = memory_address_to_byte(space, offset) & space->bytemask;;
+		cheat_region[region_count].endoffset = memory_address_to_byte(space, offset + length - 1) & space->bytemask;;
+		cheat_region[region_count].share = 0;
+		cheat_region[region_count].disabled = FALSE;
+		region_count++;
 	}
 
-	endoffset = memory_address_to_byte(space, offset + length - 1) & space->bytemask;
-	offset = memory_address_to_byte(space, offset) & space->bytemask;
-
-	/* counts the writable bytes in the area */
-	for (curaddr = offset; curaddr <= endoffset; curaddr += cheat.width)
-		if (cheat_address_is_valid(space, curaddr))
-			real_length++;
+	/* determine the writable extent of each region in total */
+	for (i = 0; i <= region_count; i++)
+		if (!cheat_region[i].disabled)
+			for (curaddr = cheat_region[i].offset; curaddr <= cheat_region[i].endoffset; curaddr += cheat.width)
+				if (cheat_address_is_valid(space, curaddr))
+					real_length++;
 
 	if (real_length == 0)
 	{
@@ -1831,16 +1867,18 @@ static void execute_cheatinit(running_machine *machine, int ref, int params, con
 	}
 
 	/* initialize cheatmap in the selected space */
-	for (curaddr = offset; curaddr <= endoffset; curaddr += cheat.width)
-		if (cheat_address_is_valid(space, curaddr))
-		{
-			cheat.cheatmap[active_cheat].previous_value = cheat_read_extended(&cheat, space, curaddr);
-			cheat.cheatmap[active_cheat].first_value = cheat.cheatmap[active_cheat].previous_value;
-			cheat.cheatmap[active_cheat].offset = curaddr;
-			cheat.cheatmap[active_cheat].state = 1;
-			cheat.cheatmap[active_cheat].undo = 0;
-			active_cheat++;
-		}
+	for (i = 0; i < region_count; i++)
+		if (!cheat_region[i].disabled)
+			for (curaddr = cheat_region[i].offset; curaddr <= cheat_region[i].endoffset; curaddr += cheat.width)
+				if (cheat_address_is_valid(space, curaddr))
+				{
+					cheat.cheatmap[active_cheat].previous_value = cheat_read_extended(&cheat, space, curaddr);
+					cheat.cheatmap[active_cheat].first_value = cheat.cheatmap[active_cheat].previous_value;
+					cheat.cheatmap[active_cheat].offset = curaddr;
+					cheat.cheatmap[active_cheat].state = 1;
+					cheat.cheatmap[active_cheat].undo = 0;
+					active_cheat++;
+				}
 
 	debug_console_printf(machine, "%u cheat initialized\n", active_cheat);
 }
@@ -2067,7 +2105,7 @@ static void execute_cheatlist(running_machine *machine, int ref, int params, con
 				active_cheat++;
 				fprintf(f, "  <cheat desc=\"Possibility %d : %s (%s)\">\n", active_cheat, core_i64_hex_format(address, space->logaddrchars), core_i64_hex_format(value, cheat.width * 2));
 				fprintf(f, "    <script state=\"run\">\n");
-				fprintf(f, "      <action>%s.%c%c@%s=%s</action>\n", cpu->tag, spaceletter, sizeletter, core_i64_hex_format(address, space->logaddrchars), core_i64_hex_format(cheat_byte_swap(&cheat, cheat.cheatmap[cheatindex].first_value) & sizemask, cheat.width * 2));
+				fprintf(f, "      <action>%s.p%c%c@%s=%s</action>\n", cpu->tag, spaceletter, sizeletter, core_i64_hex_format(address, space->logaddrchars), core_i64_hex_format(cheat_byte_swap(&cheat, cheat.cheatmap[cheatindex].first_value) & sizemask, cheat.width * 2));
 				fprintf(f, "    </script>\n");
 				fprintf(f, "  </cheat>\n\n");
 			}