diff --git a/CHANGES b/CHANGES
index 5349ac9d5..a9c5ce82c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -11,6 +11,7 @@ Bugfixes:
  - GBA Cheats: Fix GameShark ROM patches
  - GB MBC: Fix initializing MBC when no ROM is loaded
  - VFS: Fix resizing memory chunks when not needed
+ - GB Memory: Fix patching ROM bank 0
 Misc:
  - PSP2: Improved controller rumble
  - GB, GBA: Prevent loading null ROMs
diff --git a/src/gb/gb.c b/src/gb/gb.c
index ba6a26194..0a9aa8647 100644
--- a/src/gb/gb.c
+++ b/src/gb/gb.c
@@ -240,6 +240,9 @@ void GBSavedataUnmask(struct GB* gb) {
 
 void GBUnloadROM(struct GB* gb) {
 	// TODO: Share with GBAUnloadROM
+	if (gb->memory.rom && gb->memory.romBase != gb->memory.rom && gb->memory.romBase != gb->pristineRom) {
+		free(gb->memory.romBase);
+	}
 	if (gb->memory.rom && gb->pristineRom != gb->memory.rom) {
 		if (gb->yankedRomSize) {
 			gb->yankedRomSize = 0;
@@ -247,9 +250,6 @@ void GBUnloadROM(struct GB* gb) {
 		mappedMemoryFree(gb->memory.rom, GB_SIZE_CART_MAX);
 		gb->memory.rom = gb->pristineRom;
 	}
-	if (gb->memory.rom && gb->memory.romBase != gb->memory.rom) {
-		free(gb->memory.romBase);
-	}
 	gb->memory.rom = 0;
 
 	if (gb->romVf) {
diff --git a/src/gb/memory.c b/src/gb/memory.c
index 43f39ec21..fa630994c 100644
--- a/src/gb/memory.c
+++ b/src/gb/memory.c
@@ -508,8 +508,8 @@ void GBPatch8(struct LR35902Core* cpu, uint16_t address, int8_t value, int8_t* o
 	case GB_REGION_CART_BANK0 + 2:
 	case GB_REGION_CART_BANK0 + 3:
 		_pristineCow(gb);
-		oldValue = memory->rom[address & (GB_SIZE_CART_BANK0 - 1)];
-		memory->rom[address & (GB_SIZE_CART_BANK0 - 1)] =  value;
+		oldValue = memory->romBase[address & (GB_SIZE_CART_BANK0 - 1)];
+		memory->romBase[address & (GB_SIZE_CART_BANK0 - 1)] =  value;
 		break;
 	case GB_REGION_CART_BANK1:
 	case GB_REGION_CART_BANK1 + 1:
@@ -652,5 +652,8 @@ void _pristineCow(struct GB* gb) {
 	gb->memory.rom = anonymousMemoryMap(GB_SIZE_CART_MAX);
 	memcpy(gb->memory.rom, gb->pristineRom, gb->memory.romSize);
 	memset(((uint8_t*) gb->memory.rom) + gb->memory.romSize, 0xFF, GB_SIZE_CART_MAX - gb->memory.romSize);
+	if (gb->pristineRom == gb->memory.romBase) {
+		gb->memory.romBase = gb->memory.rom;
+	}
 	GBMBCSwitchBank(&gb->memory, gb->memory.currentBank);
 }