@@ -196,8 +196,13 @@ case BASE_CART0_EX:
 	case BASE_CART1:
 	case BASE_CART1_EX:
 	case BASE_CART2:
+		return ((uint16_t*) gbaMemory->rom)[(address & (SIZE_CART0 - 1)) >> 1];
 	case BASE_CART2_EX:
-		return ((uint16_t*) gbaMemory->rom)[(address & (SIZE_CART0 - 1)) >> 1];
+		if ((address & (SIZE_CART0 - 1)) < gbaMemory->romSize) {
+			return ((uint16_t*) gbaMemory->rom)[(address & (SIZE_CART0 - 1)) >> 1];
+		} else {
+			return GBASavedataReadEEPROM(&gbaMemory->savedata);
+		}
 	case BASE_CART_SRAM:
 		break;
 	default:
@@ -309,8 +314,6 @@ ((int32_t*) gbaMemory->p->video.oam.raw)[(address & (SIZE_OAM - 1)) >> 2] = value;
 		break;
 	case BASE_CART0:
 		break;
-	case BASE_CART2_EX:
-		break;
 	case BASE_CART_SRAM:
 		break;
 	default:
@@ -345,6 +348,10 @@ break;
 	case BASE_CART0:
 		break;
 	case BASE_CART2_EX:
+		if (gbaMemory->savedata.type == SAVEDATA_NONE) {
+			GBASavedataInitEEPROM(&gbaMemory->savedata);
+		}
+		GBASavedataWriteEEPROM(&gbaMemory->savedata, value);
 		break;
 	case BASE_CART_SRAM:
 		break;
@@ -372,8 +379,6 @@ break;
 	case BASE_OAM:
 		break;
 	case BASE_CART0:
-		break;
-	case BASE_CART2_EX:
 		break;
 	case BASE_CART_SRAM:
 		if (gbaMemory->savedata.type == SAVEDATA_NONE) {

@@ -5,6 +5,8 @@ #include "arm.h"
 
 #include "gba-savedata.h"
 
+#include <string.h>
+
 enum GBAMemoryRegion {
 	REGION_BIOS = 0x0,
 	REGION_WORKING_RAM = 0x2,
@@ -111,6 +113,7 @@ uint32_t* rom;
 	uint16_t io[SIZE_IO >> 1];
 
 	struct GBASavedata savedata;
+	size_t romSize;
 
 	char waitstates32[256];
 	char waitstates16[256];

@@ -43,7 +43,7 @@ GBALog(GBA_LOG_WARN, "Cannot open savedata file %s", savedata->filename);
 		return;
 	}
 	// mmap enough so that we can expand the file if we need to
-	savedata->data = mmap(0, SIZE_CART_FLASH1M, PROT_READ | PROT_WRITE, 0, savedata->fd, 0);
+	savedata->data = mmap(0, SIZE_CART_FLASH1M, PROT_READ | PROT_WRITE, MAP_SHARED, savedata->fd, 0);
 
 	off_t end = lseek(savedata->fd, 0, SEEK_END);
 	if (end < SIZE_CART_FLASH512) {
@@ -52,6 +52,22 @@ memset(&savedata->data[end], 0xFF, SIZE_CART_SRAM - end);
 	}
 }
 
+void GBASavedataInitEEPROM(struct GBASavedata* savedata) {
+	savedata->type = SAVEDATA_EEPROM;
+	savedata->fd = open(savedata->filename, O_RDWR | O_CREAT, 0666);
+	if (savedata->fd < 0) {
+		GBALog(GBA_LOG_WARN, "Cannot open savedata file %s", savedata->filename);
+		return;
+	}
+	savedata->data = mmap(0, SIZE_CART_EEPROM, PROT_READ | PROT_WRITE, MAP_SHARED, savedata->fd, 0);
+
+	off_t end = lseek(savedata->fd, 0, SEEK_END);
+	if (end < SIZE_CART_EEPROM) {
+		ftruncate(savedata->fd, SIZE_CART_EEPROM);
+		memset(&savedata->data[end], 0xFF, SIZE_CART_EEPROM - end);
+	}
+}
+
 void GBASavedataInitSRAM(struct GBASavedata* savedata) {
 	savedata->type = SAVEDATA_SRAM;
 	savedata->fd = open(savedata->filename, O_RDWR | O_CREAT, 0666);
@@ -73,8 +89,21 @@ memset(&savedata->data[end], 0xFF, SIZE_CART_SRAM - end);
 	}
 }
 
+
 void GBASavedataWriteFlash(struct GBASavedata* savedata, uint8_t value) {
 	(void)(savedata);
 	(void)(value);
 	GBALog(GBA_LOG_STUB, "Flash memory unimplemented");
 }
+
+void GBASavedataWriteEEPROM(struct GBASavedata* savedata, uint16_t value) {
+	(void)(savedata);
+	(void)(value);
+	GBALog(GBA_LOG_STUB, "EEPROM unimplemented");
+}
+
+uint16_t GBASavedataReadEEPROM(struct GBASavedata* savedata) {
+	(void)(savedata);
+	GBALog(GBA_LOG_STUB, "EEPROM unimplemented");
+	return 0;
+}

@@ -26,8 +26,12 @@ void GBASavedataInit(struct GBASavedata* savedata, const char* filename);
 void GBASavedataDeinit(struct GBASavedata* savedata);
 
 void GBASavedataInitFlash(struct GBASavedata* savedata);
+void GBASavedataInitEEPROM(struct GBASavedata* savedata);
 void GBASavedataInitSRAM(struct GBASavedata* savedata);
 
 void GBASavedataWriteFlash(struct GBASavedata* savedata, uint8_t value);
+
+uint16_t GBASavedataReadEEPROM(struct GBASavedata* savedata);
+void GBASavedataWriteEEPROM(struct GBASavedata* savedata, uint16_t value);
 
 #endif

@@ -11,6 +11,7 @@ #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
 
 enum {
 	SP_BASE_SYSTEM = 0x03FFFF00,
@@ -228,7 +229,10 @@ gba->debugger = debugger;
 }
 
 void GBALoadROM(struct GBA* gba, int fd) {
+	struct stat info;
 	gba->memory.rom = mmap(0, SIZE_CART0, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+	fstat(fd, &info);
+	gba->memory.romSize = info.st_size;
 	// TODO: error check
 }