0.7

README.md

@@ -15,7 +15,8 @@ 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`:
@@ -24,6 +25,8 @@ Set `type` to `1` or `2`:
 
 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": [

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 = "0.7"
 default_file = "LK_MULTIMENU_<CODE>.gba"
 
 ################################
@@ -83,19 +83,27 @@ 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 +126,10 @@ 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"]
@@ -166,6 +178,13 @@ 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:
@@ -310,7 +329,7 @@ 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 +339,7 @@ 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

@@ -215,14 +215,11 @@ IWRAM_CODE u8 BootGame(ItemConfig config, FlashStatus status)
 	if (_flash_type == 0)
 		return 1;
 
-	// Temporarily store SRAM values 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[2] = *(vu8 *)MAPPER_CONFIG3;
-		sram_register_backup[3] = *(vu8 *)MAPPER_CONFIG4;
-	}
+	// Temporarily store SRAM values located at mapper registers
+	sram_register_backup[0] = *(vu8 *)MAPPER_CONFIG1;
+	sram_register_backup[1] = *(vu8 *)MAPPER_CONFIG2;
+	sram_register_backup[2] = *(vu8 *)MAPPER_CONFIG3;
+	sram_register_backup[3] = *(vu8 *)MAPPER_CONFIG4;
 
 	// Enable SRAM access
 	*(vu8 *)MAPPER_CONFIG4 = 1;

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_
 {