New config option + autoboot if there is only one game in the list

Makefile

@@ -183,7 +183,9 @@ $(shell touch $(CURDIR)/../$(SOURCES)/version.h)
 %.gba: %.elf
 	@$(OBJCOPY) -O binary $< $@
 	@gbafix $@ "-tLK MULTIMENU" "-cAGBJ" "-mLK" "-r0"
+	@echo Copying to ROM builder folder
 	@cp $@ "$(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))/rom_builder/lk_multimenu.gba"
+	@echo Done!
 
 #---------------------------------------------------------------------------------------
 endif

README.md

@@ -15,15 +15,19 @@ The following section must be edited in order to specify the cartridge type to u
 ```json
 "cartridge": {
 	"type": 2,
-	"battery_present": false
+	"battery_present": false,
+	"min_rom_size": 4194304
 },
 ```
 Set `type` to `1` or `2`:
-- `1` = MSP55LV100S (e.g. The Legend of Zelda Collection - Classic Edition 7-in-1)
+- `1` = MSP55LV100S (e.g. The Legend of Zelda Collection - Classic Edition 7-in-1, 64 MiB)
-- `2` = 6600M0U0BE (e.g. 369IN1 2048M)
+- `2` = 6600M0U0BE (e.g. 369IN1 2048M, 256 MiB)
+- `3` = MSP54LV100 (e.g. The Legend of Zelda Collection - Classic Edition 7-in-1, 128 MiB)
 
 Set `battery_present` to `true` or `false`. This will enable enhanced save data handling which will only be functional with a working battery.
 
+Set `min_rom_size` to whatever your cartridge supports as the smallest possible ROM size. Many newer cartridges only support ROMs no smaller than 4 MiB (`4194304`) while some older cartridges can go as low as 512 KiB (`524288`).
+
 In the `games` section, you can edit the game-related stuff:
 ```json
 "games": [
@@ -47,6 +51,7 @@ In the `games` section, you can edit the game-related stuff:
   - `6` = Pokémon Black & White condensed battle font
 - `save_slot` defines which save slot your game uses. Set it to `null` for no saving or a number starting from `1`. Multiple games can share a save slot.
 - `map_256m`, if set to `true`, can serve as a workaround for a glitch with the cartridge mapper that causes games to freeze with screeching noises upon launch.
+- `keys` will let you specify a list of keys that must be held down at startup for this ROM to appear in the menu, e. g. `[ "L", "R", "DOWN" ]`.
 
 ### ROM Builder Command Line Arguments
 
@@ -71,15 +76,18 @@ If the cartridge has a battery installed, the ROMs must be SRAM-patched with [GB
 
 If the cartridge has no battery installed, the ROMs must be patched for batteryless SRAM saving with maniac's [Automatic batteryless saving patcher](https://github.com/metroid-maniac/gba-auto-batteryless-patcher/).
 
+On battery-equipped cartridges, when starting a game from the menu, the previously played game's save data will be read from SRAM and stored to permanent flash memory. To skip this, you can hold the SELECT button while starting the game.
+
 ## Compatibility
 Tested repro cartridges:
-- 100BS6600_48BALL_V4 with 6600M0U0BE
 - 100SOP with MSP55LV100S
+- 100BS6600_48BALL_V4 with 6600M0U0BE
+- SUN100S_MSP54_XXX_BGA48 with MSP54LV100
 
 The generated compilation ROM can be written and read using a [GBxCart RW v1.4+](https://www.gbxcart.com/) device by insideGadgets and the [FlashGBX](https://github.com/lesserkuma/FlashGBX) software.
 
 ## Thanks
-Thanks to FraX, Ausar, liuyunx, BennVenn
+Thanks to FraX, Ausar, liuyunx, BennVenn, Jenetrix
 
 ## Screenshots
 

rom_builder/rom_builder.py

@@ -5,7 +5,7 @@
 import sys, os, glob, json, math, re, struct, hashlib, argparse, datetime
 
 # Configuration
-app_version = "0.3"
+app_version = "0.10"
 default_file = "LK_MULTIMENU_<CODE>.gba"
 
 ################################
@@ -51,6 +51,12 @@ cartridge_types = [
 		"sector_size":0x40000,
 		"block_size":0x80000,
 	},
+	{
+		"name":"MSP54LV100",
+		"flash_size":0x8000000,
+		"sector_size":0x20000,
+		"block_size":0x80000,
+	},
 ]
 now = datetime.datetime.now()
 log = ""
@@ -83,19 +89,27 @@ if not os.path.exists(args.config):
 	games = []
 	cartridge_type = 1
 	battery_present = False
+	min_rom_size = 0x400000
 	for file in files:
-		games.append({
+		d = {
 			"enabled": True,
 			"file": os.path.split(file)[1],
 			"title": os.path.splitext(os.path.split(file)[1])[0],
 			"title_font": 1,
 			"save_slot": save_slot,
-		})
+		}
+		with open(file, "rb") as f:
+			f.seek(0xAC)
+			code = f.read(0x4)
+			if code[:3] in (b"BPG", b"BPR"):
+				d["map_256m"] = True
+		games.append(d)
 		save_slot += 1
 	obj = {
 		"cartridge": {
 			"type": cartridge_type + 1,
 			"battery_present": battery_present,
+			"min_rom_size": min_rom_size,
 		},
 		"games": games,
 	}
@@ -118,6 +132,10 @@ else:
 		games = j["games"]
 		cartridge_type = j["cartridge"]["type"] - 1
 		battery_present = j["cartridge"]["battery_present"]
+		if "min_rom_size" in j["cartridge"]:
+			min_rom_size = j["cartridge"]["min_rom_size"]
+		else:
+			min_rom_size = 0x400000
 
 # Prepare compilation
 flash_size = cartridge_types[cartridge_type]["flash_size"]
@@ -127,6 +145,7 @@ block_size = cartridge_types[cartridge_type]["block_size"]
 block_count = flash_size // block_size
 sectors_per_block = 0x80000 // sector_size
 compilation = bytearray()
+roms_keys = [0]
 for i in range(flash_size // 0x2000000):
 	chunk = bytearray([0xFF] * 0x2000000)
 	compilation += chunk
@@ -166,6 +185,13 @@ for game in games:
 		x = 0x80000
 		while (x < size): x *= 2
 		size = x
+	if size < 0x400000:
+		with open(f"roms/{game['file']}", "rb") as f:
+			buffer = f.read()
+			if b"Batteryless mod by Lesserkuma" in buffer:
+				size = max(0x400000, min_rom_size)
+			else:
+				size = max(size, min_rom_size)
 	game["index"] = index
 	game["size"] = size
 	if "title_font" in game:
@@ -173,7 +199,36 @@ for game in games:
 	else:
 		game["title_font"] = 0
 	game["sector_count"] = int(size / sector_size)
-
+	
+	# Hidden ROMs
+	keys = 0
+	if "keys" in game:
+		for key in game["keys"]:
+			if key.upper() == "A":
+				keys |= (1 << 0)
+			elif key.upper() == "B":
+				keys |= (1 << 1)
+			elif key.upper() == "SELECT":
+				keys |= (1 << 2)
+			elif key.upper() == "START":
+				keys |= (1 << 3)
+			elif key.upper() == "RIGHT":
+				keys |= (1 << 4)
+			elif key.upper() == "LEFT":
+				keys |= (1 << 5)
+			elif key.upper() == "UP":
+				keys |= (1 << 6)
+			elif key.upper() == "DOWN":
+				keys |= (1 << 7)
+			elif key.upper() == "R":
+				keys |= (1 << 8)
+			elif key.upper() == "L":
+				keys |= (1 << 9)
+	game["keys"] = keys
+	if keys > 0:
+		roms_keys.append(keys)
+		roms_keys = list(set(roms_keys))
+	
 	if battery_present and game["save_slot"] is not None:
 		game["save_type"] = 2
 		game["save_slot"] -= 1
@@ -215,7 +270,6 @@ for game in games:
 
 # Read ROM data
 games.sort(key=lambda game: game["size"], reverse=True)
-c = 0
 for game in games:
 	found = False
 	for i in range(save_end_offset, len(sector_map)):
@@ -266,33 +320,39 @@ else:
 	toc_sep = "----+-----------+-----------+--------------------------------------------------"
 
 item_list = bytearray()
-for game in games:
-	title = game["title"]
-	if len(title) > 0x30: title = title[:0x2F] + "…"
 
-	table_line = \
+for key in roms_keys:
-				f"{game['index'] + 1:3d} | " \
+	c = 0
-				f"0x{game['block_offset'] * block_size:07X} | "\
+	for game in games:
-				f"0x{game['block_count'] * block_size:07X} | "
+		if game["keys"] != key: continue
-	if battery_present:
+		
-		if game['save_type'] > 0:
+		title = game["title"]
-			table_line += f"{game['save_slot']+1:2d} (0x{(save_data_sector_offset + game['save_slot']) * sector_size:07X}) | "
+		if len(title) > 0x30: title = title[:0x2F] + "…"
-		else:
+
-			table_line += "               | "
+		table_line = \
-	table_line += f"{title}"
+					f"{game['index'] + 1:3d} | " \
-	if c % 8 == 0: logp(toc_sep)
+					f"0x{game['block_offset'] * block_size:07X} | "\
-	logp(table_line)
+					f"0x{game['block_count'] * block_size:07X} | "
-	c += 1
+		if battery_present:
-	
+			if game['save_type'] > 0:
-	title = title.ljust(0x30, "\0")
+				table_line += f"{game['save_slot']+1:2d} (0x{(save_data_sector_offset + game['save_slot']) * sector_size:07X}) | "
-	item_list += bytearray(struct.pack("B", game["title_font"]))
+			else:
-	item_list += bytearray(struct.pack("B", len(game["title"])))
+				table_line += "               | "
-	item_list += bytearray(struct.pack("<H", game["block_offset"]))
+		table_line += f"{title}"
-	item_list += bytearray(struct.pack("<H", game["block_count"]))
+		if c % 8 == 0: logp(toc_sep)
-	item_list += bytearray(struct.pack("B", game["save_type"]))
+		logp(table_line)
-	item_list += bytearray(struct.pack("B", game["save_slot"]))
+		c += 1
-	item_list += bytearray([0] * 8)
+		
-	item_list += bytearray(title.encode("UTF-16LE"))
+		title = title.ljust(0x30, "\0")
+		item_list += bytearray(struct.pack("B", game["title_font"]))
+		item_list += bytearray(struct.pack("B", len(game["title"])))
+		item_list += bytearray(struct.pack("<H", game["block_offset"]))
+		item_list += bytearray(struct.pack("<H", game["block_count"]))
+		item_list += bytearray(struct.pack("B", game["save_type"]))
+		item_list += bytearray(struct.pack("B", game["save_slot"]))
+		item_list += bytearray(struct.pack("<H", game["keys"]))
+		item_list += bytearray([0] * 6)
+		item_list += bytearray(title.encode("UTF-16LE"))
 
 compilation[item_list_offset * sector_size:item_list_offset * sector_size + len(item_list)] = item_list
 rom_code = "L{:s}".format(hashlib.sha1(status + item_list).hexdigest()[:3]).upper()
@@ -310,7 +370,7 @@ logp("Menu ROM:        0x{:07X}–0x{:07X}".format(0, len(menu_rom)))
 logp("Game List:       0x{:07X}–0x{:07X}".format(item_list_offset * sector_size, item_list_offset * sector_size + len(item_list)))
 logp("Status Area:     0x{:07X}–0x{:07X}".format(status_offset * sector_size, status_offset * sector_size + 0x1000))
 logp("")
-logp("Cartridge Type:  {:d} ({:s} {:s})".format(cartridge_type, cartridge_types[cartridge_type]["name"], "with battery" if battery_present else "without battery"))
+logp("Cartridge Type:  {:d} ({:s}) {:s}".format(cartridge_type + 1, cartridge_types[cartridge_type]["name"], "with battery" if battery_present else "without battery"))
 logp("Output ROM Size: {:.2f} MiB".format(rom_size / 1024 / 1024))
 logp("Output ROM Code: {:s}".format(rom_code))
 output_file = output_file.replace("<CODE>", rom_code)
@@ -320,7 +380,7 @@ if args.split:
 		size = 0x2000000
 		if pos > len(compilation[:rom_size]): break
 		if pos + size > rom_size: size = rom_size - pos
-		output_file_part = "{:s}_part{:d}{:s}".format(os.path.splitext(output_file)[0], i + 1, os.path.splitext(output_file)[1])
+		output_file_part = "{:s}_part{:d}{:s}".format(os.path.splitext(output_file)[0], i, os.path.splitext(output_file)[1])
 		with open(output_file_part, "wb") as f: f.write(compilation[pos:pos+size])
 else:
 	with open(output_file, "wb") as f: f.write(compilation[:rom_size])

source/flash.c

@@ -66,6 +66,22 @@ IWRAM_CODE void FlashDetectType(void)
 		return;
 	}
 
+	// 1G cart with MSP54LV100S (Zelda Classic Collection 7-in-1)
+	_FLASH_WRITE(0, 0xF0);
+	_FLASH_WRITE(0xAAA, 0xA9);
+	_FLASH_WRITE(0x555, 0x56);
+	_FLASH_WRITE(0xAAA, 0x90);
+	data = *(vu32 *)AGB_ROM;
+	_FLASH_WRITE(0, 0xF0);
+	if (data == 0x227D0002)
+	{
+		REG_IE = ie;
+		flash_type = 3;
+		flash_sector_size = 0x20000;
+		FlashCalcOffsets();
+		return;
+	}
+
 	// Unknown type
 	REG_IE = ie;
 	flash_type = 0;
@@ -119,6 +135,24 @@ IWRAM_CODE void FlashEraseSector(u32 address)
 		}
 		_FLASH_WRITE(address, 0xF0F0);
 	}
+	else if (_flash_type == 3)
+	{
+		_FLASH_WRITE(0xAAA, 0xA9);
+		_FLASH_WRITE(0x555, 0x56);
+		_FLASH_WRITE(0xAAA, 0x80);
+		_FLASH_WRITE(0xAAA, 0xA9);
+		_FLASH_WRITE(0x555, 0x56);
+		_FLASH_WRITE(address, 0x30);
+		while (1)
+		{
+			__asm("nop");
+			if ((*((vu16 *)(AGB_ROM + address))) == 0xFFFF)
+			{
+				break;
+			}
+		}
+		_FLASH_WRITE(address, 0xF0);
+	}
 
 	REG_IE = ie;
 }
@@ -191,6 +225,33 @@ IWRAM_CODE void FlashWriteData(u32 address, u32 length)
 		}
 		_FLASH_WRITE(address, 0xF0F0);
 	}
+	else if (_flash_type == 3)
+	{
+		for (int j = 0; j < (int)(length / 0x40); j++)
+		{
+			_FLASH_WRITE(0xAAA, 0xA9);
+			_FLASH_WRITE(0x555, 0x56);
+			_FLASH_WRITE(address + (j * 0x40), 0x26);
+			_FLASH_WRITE(address + (j * 0x40), 0x1F);
+			u16 data = 0;
+			for (int i = 0; i < 0x40; i += 2)
+			{
+				__asm("nop");
+				data = data_buffer[(j * 0x40) + i + 1] << 8 | data_buffer[(j * 0x40) + i];
+				_FLASH_WRITE(address + (j * 0x40) + i, data);
+			}
+			_FLASH_WRITE(address + (j * 0x40), 0x2A);
+			while (1)
+			{
+				__asm("nop");
+				if (p_rom[(j * 0x20) + 0x1F] == data)
+				{
+					break;
+				}
+			}
+		}
+		_FLASH_WRITE(address, 0xF0);
+	}
 
 	REG_IE = ie;
 }
@@ -215,14 +276,11 @@ IWRAM_CODE u8 BootGame(ItemConfig config, FlashStatus status)
 	if (_flash_type == 0)
 		return 1;
 
-	// Temporarily store SRAM values at mapper registers
+	// Temporarily store SRAM values located at mapper registers
-	if (status.last_boot_save_type == SRAM_NONE)
+	sram_register_backup[0] = *(vu8 *)MAPPER_CONFIG1;
-	{
+	sram_register_backup[1] = *(vu8 *)MAPPER_CONFIG2;
-		sram_register_backup[0] = *(vu8 *)MAPPER_CONFIG1;
+	sram_register_backup[2] = *(vu8 *)MAPPER_CONFIG3;
-		sram_register_backup[1] = *(vu8 *)MAPPER_CONFIG2;
+	sram_register_backup[3] = *(vu8 *)MAPPER_CONFIG4;
-		sram_register_backup[2] = *(vu8 *)MAPPER_CONFIG3;
-		sram_register_backup[3] = *(vu8 *)MAPPER_CONFIG4;
-	}
 
 	// Enable SRAM access
 	*(vu8 *)MAPPER_CONFIG4 = 1;
@@ -243,16 +301,16 @@ IWRAM_CODE u8 BootGame(ItemConfig config, FlashStatus status)
 			FlashEraseSector((_flash_save_block_offset + status.last_boot_save_index) * _flash_sector_size);
 			FlashWriteData((_flash_save_block_offset + status.last_boot_save_index) * _flash_sector_size, SRAM_SIZE);
 		}
-
-		// Save status to flash
-		status.last_boot_save_index = config.save_index;
-		status.last_boot_save_type = config.save_type;
-		memset((void *)data_buffer, 0, 0x1000);
-		memcpy(data_buffer, &status, sizeof(status));
-		FlashEraseSector(_flash_status_block_offset * flash_sector_size);
-		FlashWriteData(_flash_status_block_offset * flash_sector_size, 0x1000);
 	}
 
+	// Save status to flash
+	status.last_boot_save_index = config.save_index;
+	status.last_boot_save_type = config.save_type;
+	memset((void *)data_buffer, 0, 0x1000);
+	memcpy(data_buffer, &status, sizeof(status));
+	FlashEraseSector(_flash_status_block_offset * flash_sector_size);
+	FlashWriteData(_flash_status_block_offset * flash_sector_size, 0x1000);
+
 	// Disable SRAM access
 	*(vu8 *)MAPPER_CONFIG4 = 0;
 

source/flash.h

@@ -15,7 +15,6 @@ Author: Lesserkuma (github.com/lesserkuma)
     }
 
 #define MAGIC_FLASH_STATUS 0x414D554B
-#define FLASH_STATUS_LOCATION 0xA0000
 
 typedef struct __attribute__((packed)) FlashStatus_
 {

source/main.c

@@ -60,6 +60,7 @@ int main(void) {
 	u8 redraw_items = 0xFF;
 	u8 roms_page = 7;
 	u16 kHeld = 0;
+	u16 kHeld_boot = 0;
 	BOOL show_debug = FALSE;
 	BOOL show_credits = FALSE;
 	BOOL boot_failed = FALSE;
@@ -90,21 +91,32 @@ int main(void) {
 	SetMode(MODE_4 | BG2_ENABLE);
 	dmaCopy(bgBitmap, (void*)AGB_VRAM+0xA000, SCREEN_WIDTH * SCREEN_HEIGHT);
 	
-	// Count number of ROMs
+	// Check on-boot keys
-	for (roms_total = 0; roms_total < 512; roms_total++) {
+	scanKeys();
-		if ((itemlist[(0x70*roms_total+1)] == 0) || (itemlist[(0x70*roms_total+1)] == 0xFF)) break;
+	kHeld = keysHeld();
+	kHeld_boot = kHeld;
+	if ((kHeld & KEY_SELECT) && (kHeld & KEY_R)) {
+		show_credits = TRUE;
+	} else if (kHeld & KEY_SELECT) {
+		show_debug = TRUE;
 	}
-	if (roms_total == 0) {
+	if (kHeld) {
-		LoadFont(2);
+		u16 itemlist_offset = 0;
-		DrawText(0, 64, ALIGN_CENTER, u"Please use the ROM Builder to", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
+		BOOL found_keys = FALSE;
-		DrawText(0, 64 + sFontSpecs.max_height, ALIGN_CENTER, u"create your own compilation.", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
+		for (itemlist_offset = 0; itemlist_offset < 0x924; itemlist_offset += 0x70) {
-		LoadFont(0);
+			memcpy(&sItemConfig, ((u8*)itemlist)+itemlist_offset, sizeof(sItemConfig));
-		DrawText(0, 127, ALIGN_CENTER, u"https://github.com/lesserkuma/GBA_MultiMenu", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
+			if (sItemConfig.title_length == 0) break;
-		DrawText(14, SCREEN_HEIGHT - sFontSpecs.max_height - 3 - FontMarginBottom, ALIGN_RIGHT, u"No ROMs", 10, font, (void*)AGB_VRAM+0xA000, FALSE);
+			if (sItemConfig.title_length == 0xFF) break;
-		REG_DISPCNT ^= 0x0010;
+			if (sItemConfig.keys == kHeld) {
-		while (1) { VBlankIntrWait(); }
+				itemlist += itemlist_offset;
+				found_keys = TRUE;
+				break;
+			}
+		}
+		if (!found_keys) {
+			kHeld = 0;
+		}
 	}
-	page_total = (roms_total + 8.0 - 1) / 8.0;
 
 	memcpy(&sFlashStatus, (void *)(AGB_ROM + flash_status_sector_offset * flash_sector_size), sizeof(sFlashStatus));
 	if ((sFlashStatus.magic != MAGIC_FLASH_STATUS) || (sFlashStatus.last_boot_menu_index >= roms_total)) {
@@ -119,15 +131,29 @@ int main(void) {
 		page_active = sFlashStatus.last_boot_menu_index / 8;
 	}
 
-	// Check on-boot keys
+	// Count number of ROMs
-	scanKeys();
+	for (roms_total = 0; roms_total < 512; roms_total++) {
-	kHeld = keysHeld();
+		memcpy(&sItemConfig, ((u8*)itemlist)+(0x70*roms_total), sizeof(sItemConfig));
-	if ((kHeld & KEY_SELECT) && (kHeld & KEY_R)) {
+		if (sItemConfig.keys != kHeld) break;
-		show_credits = TRUE;
+		if (sItemConfig.title_length == 0) break;
-	} else if (kHeld & KEY_SELECT) {
+		if (sItemConfig.title_length == 0xFF) break;
-		show_debug = TRUE;
 	}
-	
+	if (roms_total == 0) {
+		LoadFont(2);
+		DrawText(0, 64, ALIGN_CENTER, u"Please use the ROM Builder to", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
+		DrawText(0, 64 + sFontSpecs.max_height, ALIGN_CENTER, u"create your own compilation.", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
+		LoadFont(0);
+		DrawText(0, 127, ALIGN_CENTER, u"https://github.com/lesserkuma/GBA_MultiMenu", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
+		DrawText(14, SCREEN_HEIGHT - sFontSpecs.max_height - 3 - FontMarginBottom, ALIGN_RIGHT, u"No ROMs", 10, font, (void*)AGB_VRAM+0xA000, FALSE);
+		REG_DISPCNT ^= 0x0010;
+		while (1) { VBlankIntrWait(); }
+	} else if (roms_total == 1) {
+		memcpy(&sItemConfig, ((u8*)itemlist), sizeof(sItemConfig));
+		u8 error_code = BootGame(sItemConfig, sFlashStatus);
+		boot_failed = error_code;
+	}
+	page_total = (roms_total + 8.0 - 1) / 8.0;
+
 	s32 wait = 0;
 	u8 f = 0;
 	while (1) {
@@ -212,6 +238,11 @@ int main(void) {
 		// Check for menu keys
 		scanKeys();
 		kHeld = keysHeld();
+		if ((kHeld_boot == 0) || (kHeld != kHeld_boot)) {
+			kHeld_boot = 0;
+		} else {
+			kHeld = 0;
+		}
 		if (kHeld != 0) {
 			wait++;
 		} else {
@@ -233,13 +264,15 @@ int main(void) {
 				sFlashStatus.last_boot_menu_index = page_active * 8 + cursor_pos;
 				if (!show_credits && !show_debug) {
 					LoadFont(0);
-					if (sFlashStatus.battery_present == 1) {
+					DrawText(5, SCREEN_HEIGHT - sFontSpecs.max_height - 3 - FontMarginBottom, ALIGN_LEFT, u"Loading… Don't turn off the power!", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
-						DrawText(5, SCREEN_HEIGHT - sFontSpecs.max_height - 3 - FontMarginBottom, ALIGN_LEFT, u"Loading… Don't turn off the power!", 48, font, (void*)AGB_VRAM+0xA000, FALSE);
-					}
 					REG_DISPCNT ^= 0x0010;
 					dmaCopy((void*)AGB_VRAM+0xA000, (void*)AGB_VRAM, SCREEN_WIDTH * SCREEN_HEIGHT);
 					REG_DISPCNT ^= 0x0010;
 				}
+				if (kHeld & KEY_SELECT) {
+					// Skips reading latest save data from SRAM
+					sFlashStatus.last_boot_save_type = SRAM_NONE;
+				}
 				u8 error_code = BootGame(sItemConfig, sFlashStatus);
 				boot_failed = error_code;
 				redraw_items = 0xFF;

source/main.h

@@ -66,7 +66,7 @@ typedef struct ItemConfig_
 	u16 rom_size;
 	SAVE_TYPE save_type;
 	u8 save_index;
-	u16 index;
+	u16 keys;
 	u8 reserved[6];
 	u16 title[0x30];
 } ItemConfig;