-

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": [
@@ -71,15 +75,18 @@ 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 = "0.5"
+app_version = "0.9"
 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 = ""
@@ -83,6 +89,7 @@ if not os.path.exists(args.config):
 	games = []
 	cartridge_type = 1
 	battery_present = False
+	min_rom_size = 0x400000
 	for file in files:
 		d = {
 			"enabled": True,
@@ -102,6 +109,7 @@ if not os.path.exists(args.config):
 		"cartridge": {
 			"type": cartridge_type + 1,
 			"battery_present": battery_present,
+			"min_rom_size": min_rom_size,
 		},
 		"games": games,
 	}
@@ -124,6 +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"]
@@ -172,6 +184,13 @@ 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:

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;
 }
@@ -240,16 +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/main.c

@@ -233,13 +233,15 @@ 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;