@@ -114,6 +114,7 @@ uint16_t io[SIZE_IO >> 1];
 
 	struct GBASavedata savedata;
 	size_t romSize;
+	uint16_t romID;
 	int fullBios;
 
 	char waitstates32[256];

@@ -21,6 +21,14 @@ savedata->fd = -1;
 	savedata->filename = filename;
 }
 
+void GBASavedataForceType(struct GBASavedata* savedata, enum SavedataType type) {
+	if (savedata->type != SAVEDATA_NONE) {
+		GBALog(0, GBA_LOG_WARN, "Can't re-initialize savedata");
+		return;
+	}
+	savedata->type = type;
+}
+
 void GBASavedataDeinit(struct GBASavedata* savedata) {
 	switch (savedata->type) {
 	case SAVEDATA_SRAM:
@@ -43,7 +51,13 @@ savedata->type = SAVEDATA_NONE;
 }
 
 void GBASavedataInitFlash(struct GBASavedata* savedata) {
-	savedata->type = SAVEDATA_FLASH512;
+	if (savedata->type == SAVEDATA_NONE) {
+		savedata->type = SAVEDATA_FLASH512;
+	}
+	if (savedata->type != SAVEDATA_FLASH512 && savedata->type != SAVEDATA_FLASH1M) {
+		GBALog(0, GBA_LOG_WARN, "Can't re-initialize savedata");
+		return;
+	}
 	savedata->fd = open(savedata->filename, O_RDWR | O_CREAT, 0666);
 	off_t end;
 	int flags = MAP_SHARED;
@@ -66,7 +80,12 @@ }
 }
 
 void GBASavedataInitEEPROM(struct GBASavedata* savedata) {
-	savedata->type = SAVEDATA_EEPROM;
+	if (savedata->type == SAVEDATA_NONE) {
+		savedata->type = SAVEDATA_EEPROM;
+	} else {
+		GBALog(0, GBA_LOG_WARN, "Can't re-initialize savedata");
+		return;
+	}
 	savedata->fd = open(savedata->filename, O_RDWR | O_CREAT, 0666);
 	off_t end;
 	int flags = MAP_SHARED;
@@ -87,7 +106,12 @@ }
 }
 
 void GBASavedataInitSRAM(struct GBASavedata* savedata) {
-	savedata->type = SAVEDATA_SRAM;
+	if (savedata->type == SAVEDATA_NONE) {
+		savedata->type = SAVEDATA_SRAM;
+	} else {
+		GBALog(0, GBA_LOG_WARN, "Can't re-initialize savedata");
+		return;
+	}
 	savedata->fd = open(savedata->filename, O_RDWR | O_CREAT, 0666);
 	off_t end;
 	int flags = MAP_SHARED;

@@ -68,8 +68,15 @@
 	enum FlashStateMachine flashState;
 };
 
+struct SavedataOverride {
+	uint32_t id;
+	enum SavedataType type;
+};
+
 void GBASavedataInit(struct GBASavedata* savedata, const char* filename);
 void GBASavedataDeinit(struct GBASavedata* savedata);
+
+void GBASavedataForceType(struct GBASavedata* savedata, enum SavedataType type);
 
 void GBASavedataInitFlash(struct GBASavedata* savedata);
 void GBASavedataInitEEPROM(struct GBASavedata* savedata);

@@ -22,9 +22,16 @@ SP_BASE_IRQ = 0x03FFFFA0,
 	SP_BASE_SUPERVISOR = 0x03FFFFE0
 };
 
+static const struct SavedataOverride _savedataOverrides[] = {
+	{ 'EEPB', SAVEDATA_FLASH1M },
+	{ 0, 0 }
+};
+
 static void GBAProcessEvents(struct ARMBoard* board);
 static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles);
 static void GBAHitStub(struct ARMBoard* board, uint32_t opcode);
+
+static void _checkOverrides(struct GBA* gba, uint32_t code);
 
 void GBAInit(struct GBA* gba) {
 	gba->errno = GBA_NO_ERROR;
@@ -270,6 +277,7 @@ gba->memory.rom = mmap(0, SIZE_CART0, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 	gba->activeFile = fname;
 	fstat(fd, &info);
 	gba->memory.romSize = info.st_size;
+	_checkOverrides(gba, ((struct GBACartridge*) gba->memory.rom)->id);
 	// TODO: error check
 }
 
@@ -432,3 +440,27 @@ } else {
 		ARMDebuggerEnter(gbaBoard->p->debugger);
 	}
 }
+
+void _checkOverrides(struct GBA* gba, uint32_t id) {
+	int i;
+	for (i = 0; _savedataOverrides[i].id; ++i) {
+		if (_savedataOverrides[i].id == id) {
+			gba->memory.savedata.type = _savedataOverrides[i].type;
+			switch (_savedataOverrides[i].type) {
+				case SAVEDATA_FLASH512:
+				case SAVEDATA_FLASH1M:
+					GBASavedataInitFlash(&gba->memory.savedata);
+					break;
+				case SAVEDATA_EEPROM:
+					GBASavedataInitEEPROM(&gba->memory.savedata);
+					break;
+				case SAVEDATA_SRAM:
+					GBASavedataInitSRAM(&gba->memory.savedata);
+					break;
+				case SAVEDATA_NONE:
+					break;
+			}
+			return;
+		}
+	}
+}

@@ -93,6 +93,21 @@ const char* errstr;
 	int logLevel;
 };
 
+struct GBACartridge {
+	uint32_t entry;
+	uint8_t logo[156];
+	char title[12];
+	uint32_t id;
+	uint16_t maker;
+	uint8_t type;
+	uint8_t unit;
+	uint8_t device;
+	uint8_t reserved[7];
+	uint8_t version;
+	uint8_t checksum;
+	// And ROM data...
+};
+
 void GBAInit(struct GBA* gba);
 void GBADeinit(struct GBA* gba);