diff --git a/src/gba/cheats.c b/src/gba/cheats.c
index 9fd006a75..440233243 100644
--- a/src/gba/cheats.c
+++ b/src/gba/cheats.c
@@ -12,6 +12,9 @@ const uint32_t GBA_CHEAT_DEVICE_ID = 0xABADC0DE;
 
 DEFINE_VECTOR(GBACheatList, struct GBACheat);
 
+static const uint32_t _gsa1S[4] = { 0x09F4FBBD, 0x9681884A, 0x352027E9, 0xF3DEE5A7 };
+static const uint32_t _gsa3S[4] = { 0x7AA9648F, 0x7FAE6994, 0xC0EFAAD5, 0x42712C57 };
+
 static int32_t _readMem(struct ARMCore* cpu, uint32_t address, int width) {
 	switch (width) {
 	case 1:
@@ -105,6 +108,126 @@ static const char* _hex16(const char* line, uint16_t* out) {
 	return line;
 }
 
+// http://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm
+static void _decryptGameShark(uint32_t* op1, uint32_t* op2, const uint32_t* seeds) {
+	uint32_t sum = 0xC6EF3720;
+	int i;
+	for (i = 0; i < 32; ++i) {
+		*op2 -= ((*op1 << 4) + seeds[2]) ^ (*op1 + sum) ^ ((*op1 >> 5) + seeds[3]);
+		*op1 -= ((*op2 << 4) + seeds[0]) ^ (*op2 + sum) ^ ((*op2 >> 5) + seeds[1]);
+		sum -= 0x9E3779B9;
+	}
+}
+
+static bool _addGSA1(struct GBACheatSet* cheats, uint32_t op1, uint32_t op2) {
+	enum GBAGameSharkType type = op1 >> 28;
+	struct GBACheat* cheat = 0;
+
+	if (cheats->incompleteCheat) {
+		if (cheats->remainingAddresses > 0) {
+			cheat = GBACheatListAppend(&cheats->list);
+			cheat->type = CHEAT_ASSIGN;
+			cheat->width = 4;
+			cheat->address = op1;
+			cheat->operand = cheats->incompleteCheat->operand;
+			cheat->repeat = 1;
+			--cheats->remainingAddresses;
+		}
+		if (cheats->remainingAddresses > 0) {
+			cheat = GBACheatListAppend(&cheats->list);
+			cheat->type = CHEAT_ASSIGN;
+			cheat->width = 4;
+			cheat->address = op2;
+			cheat->operand = cheats->incompleteCheat->operand;
+			cheat->repeat = 1;
+			--cheats->remainingAddresses;
+		}
+		if (cheats->remainingAddresses == 0) {
+			cheats->incompleteCheat = 0;
+		}
+		return true;
+	}
+
+	switch (type) {
+	case GSA_ASSIGN_1:
+		cheat = GBACheatListAppend(&cheats->list);
+		cheat->type = CHEAT_ASSIGN;
+		cheat->width = 1;
+		cheat->address = op1 & 0x0FFFFFFF;
+		break;
+	case GSA_ASSIGN_2:
+		cheat = GBACheatListAppend(&cheats->list);
+		cheat->type = CHEAT_ASSIGN;
+		cheat->width = 2;
+		cheat->address = op1 & 0x0FFFFFFF;
+		break;
+	case GSA_ASSIGN_4:
+		cheat = GBACheatListAppend(&cheats->list);
+		cheat->type = CHEAT_ASSIGN;
+		cheat->width = 4;
+		cheat->address = op1 & 0x0FFFFFFF;
+		break;
+	case GSA_ASSIGN_LIST:
+		cheats->remainingAddresses = (op1 & 0xFFFF) - 1;
+		cheat = GBACheatListAppend(&cheats->list);
+		cheat->type = CHEAT_ASSIGN;
+		cheat->width = 4;
+		cheat->address = op2;
+		cheats->incompleteCheat = cheat;
+		break;
+	case GSA_PATCH:
+		if (cheats->nRomPatches >= MAX_ROM_PATCHES) {
+			return false;
+		}
+		cheats->romPatches[cheats->nRomPatches].address = (op1 & 0xFFFFFF) << 1;
+		cheats->romPatches[cheats->nRomPatches].newValue = op2;
+		cheats->romPatches[cheats->nRomPatches].applied = false;
+		++cheats->nRomPatches;
+		return true;
+	case GSA_BUTTON:
+		// TODO: Implement button
+		return false;
+	case GSA_IF_EQ:
+		if (op1 == 0xDEADFACE) {
+			// TODO: Change seeds
+			return false;
+		}
+		cheat = GBACheatListAppend(&cheats->list);
+		cheat->type = CHEAT_IF_EQ;
+		cheat->width = 2;
+		cheat->address = op1 & 0x0FFFFFFF;
+		break;
+	case GSA_IF_EQ_RANGE:
+		cheat = GBACheatListAppend(&cheats->list);
+		cheat->type = CHEAT_IF_EQ;
+		cheat->width = 2;
+		cheat->address = op2 & 0x0FFFFFFF;
+		cheat->operand = op1 & 0xFFFF;
+		cheat->repeat = (op1 >> 16) & 0xFF;
+		return true;
+	case GSA_HOOK:
+		if (cheats->hookAddress) {
+			return false;
+		}
+		cheats->hookAddress = BASE_CART0 | (op1 & (SIZE_CART0 - 1));
+		cheats->hookMode = MODE_THUMB;
+		return true;
+	default:
+		return false;
+	}
+	cheat->operand = op2;
+	cheat->repeat = 1;
+	return false;
+}
+
+static bool _addGSA3(struct GBACheatSet* cheats, uint32_t op1, uint32_t op2) {
+	// TODO
+	UNUSED(cheats);
+	UNUSED(op1);
+	UNUSED(op2);
+	return false;
+}
+
 static void _addBreakpoint(struct GBACheatDevice* device) {
 	if (!device->cheats || !device->p) {
 		return;
@@ -119,6 +242,34 @@ static void _removeBreakpoint(struct GBACheatDevice* device) {
 	GBAClearBreakpoint(device->p, device->cheats->hookAddress, device->cheats->hookMode, device->cheats->patchedOpcode);
 }
 
+static void _patchROM(struct GBACheatDevice* device) {
+	if (!device->cheats || !device->p) {
+		return;
+	}
+	int i;
+	for (i = 0; i < device->cheats->nRomPatches; ++i) {
+		if (device->cheats->romPatches[i].applied) {
+			continue;
+		}
+		GBAPatch16(device->p->cpu, device->cheats->romPatches[i].address, device->cheats->romPatches[i].newValue, &device->cheats->romPatches[i].oldValue);
+		device->cheats->romPatches[i].applied = true;
+	}
+}
+
+static void _unpatchROM(struct GBACheatDevice* device) {
+	if (!device->cheats || !device->p) {
+		return;
+	}
+	int i;
+	for (i = 0; i < device->cheats->nRomPatches; ++i) {
+		if (!device->cheats->romPatches[i].applied) {
+			continue;
+		}
+		GBAPatch16(device->p->cpu, device->cheats->romPatches[i].address, device->cheats->romPatches[i].oldValue, 0);
+		device->cheats->romPatches[i].applied = false;
+	}
+}
+
 static void GBACheatDeviceInit(struct ARMCore*, struct ARMComponent*);
 static void GBACheatDeviceDeinit(struct ARMComponent*);
 
@@ -134,6 +285,8 @@ void GBACheatSetInit(struct GBACheatSet* set) {
 	GBACheatListInit(&set->list, 4);
 	set->incompleteCheat = 0;
 	set->patchedOpcode = 0;
+	set->gsaVersion = 0;
+	set->remainingAddresses = 0;
 }
 
 void GBACheatSetDeinit(struct GBACheatSet* set) {
@@ -150,8 +303,10 @@ void GBACheatAttachDevice(struct GBA* gba, struct GBACheatDevice* device) {
 
 void GBACheatInstallSet(struct GBACheatDevice* device, struct GBACheatSet* cheats) {
 	_removeBreakpoint(device);
+	_unpatchROM(device);
 	device->cheats = cheats;
 	_addBreakpoint(device);
+	_patchROM(device);
 }
 
 bool GBACheatAddCodeBreaker(struct GBACheatSet* cheats, uint32_t op1, uint16_t op2) {
@@ -278,9 +433,86 @@ bool GBACheatAddCodeBreakerLine(struct GBACheatSet* cheats, const char* line) {
 	return GBACheatAddCodeBreaker(cheats, op1, op2);
 }
 
+bool GBACheatAddGameShark(struct GBACheatSet* set, uint32_t op1, uint32_t op2) {
+	uint32_t o1 = op1;
+	uint32_t o2 = op2;
+	switch (set->gsaVersion) {
+	case 0:
+		// Try to detect GameShark version
+		_decryptGameShark(&o1, &o2, _gsa1S);
+		if ((o1 & 0xF0000000) == 0xF0000000 && !(o2 & 0xFFFFFCFE)) {
+			set->gsaVersion = 1;
+			memcpy(set->gsaSeeds, _gsa1S, 4 * sizeof(uint32_t));
+			return _addGSA1(set, o1, o2);
+		}
+		o1 = op1;
+		o2 = op2;
+		_decryptGameShark(&o1, &o2, _gsa3S);
+		if ((o1 & 0xFE000000) == 0xC4000000 && !(o2 & 0xFFFF0000)) {
+			set->gsaVersion = 3;
+			memcpy(set->gsaSeeds, _gsa3S, 4 * sizeof(uint32_t));
+			return _addGSA3(set, o1, o2);
+		}
+		break;
+	case 1:
+		_decryptGameShark(&o1, &o2, set->gsaSeeds);
+		return _addGSA1(set, o1, o2);
+	case 3:
+		_decryptGameShark(&o1, &o2, set->gsaSeeds);
+		return _addGSA3(set, o1, o2);
+	}
+	return false;
+}
+
+bool GBACheatAddGameSharkLine(struct GBACheatSet* cheats, const char* line) {
+	uint32_t op1;
+	uint32_t op2;
+	line = _hex32(line, &op1);
+	if (!line) {
+		return false;
+	}
+	while (*line == ' ') {
+		++line;
+	}
+	line = _hex32(line, &op2);
+	if (!line) {
+		return false;
+	}
+	return GBACheatAddGameShark(cheats, op1, op2);
+}
+
+bool GBACheatAddLine(struct GBACheatSet* cheats, const char* line) {
+	uint32_t op1;
+	uint16_t op2;
+	uint16_t op3;
+	line = _hex32(line, &op1);
+	if (!line) {
+		return false;
+	}
+	while (isspace(line[0])) {
+		++line;
+	}
+	line = _hex16(line, &op2);
+	if (!line) {
+		return false;
+	}
+	if (isspace(line[0])) {
+		return GBACheatAddCodeBreaker(cheats, op1, op2);
+	}
+	line = _hex16(line, &op3);
+	if (!line) {
+		return false;
+	}
+	uint32_t realOp2 = op2;
+	realOp2 <<= 16;
+	realOp2 |= op3;
+	return GBACheatAddGameShark(cheats, op1, realOp2);
+}
+
 void GBACheatRefresh(struct GBACheatDevice* device) {
 	bool condition = true;
 	int conditionRemaining = 0;
+	_patchROM(device);
 
 	size_t nCodes = GBACheatListSize(&device->cheats->list);
 	size_t i;
@@ -358,4 +590,4 @@ void GBACheatDeviceInit(struct ARMCore* cpu, struct ARMComponent* component) {
 void GBACheatDeviceDeinit(struct ARMComponent* component) {
 	struct GBACheatDevice* device = (struct GBACheatDevice*) component;
 	_removeBreakpoint(device);
-}
\ No newline at end of file
+}
diff --git a/src/gba/cheats.h b/src/gba/cheats.h
index 633565d7c..24559d009 100644
--- a/src/gba/cheats.h
+++ b/src/gba/cheats.h
@@ -11,6 +11,8 @@
 #include "arm.h"
 #include "util/vector.h"
 
+#define MAX_ROM_PATCHES 4
+
 enum GBACheatType {
 	CHEAT_ASSIGN,
 	CHEAT_AND,
@@ -42,6 +44,18 @@ enum GBACodeBreakerType {
 	CB_IF_AND = 0xF,
 };
 
+enum GBAGameSharkType {
+	GSA_ASSIGN_1 = 0x0,
+	GSA_ASSIGN_2 = 0x1,
+	GSA_ASSIGN_4 = 0x2,
+	GSA_ASSIGN_LIST = 0x3,
+	GSA_PATCH = 0x6,
+	GSA_BUTTON = 0x8,
+	GSA_IF_EQ = 0xD,
+	GSA_IF_EQ_RANGE = 0xE,
+	GSA_HOOK = 0xF
+};
+
 struct GBACheat {
 	enum GBACheatType type;
 	int width;
@@ -62,6 +76,18 @@ struct GBACheatSet {
 
 	struct GBACheat* incompleteCheat;
 	uint32_t patchedOpcode;
+
+	struct GBACheatPatch {
+		uint32_t address;
+		int16_t newValue;
+		int16_t oldValue;
+		bool applied;
+	} romPatches[MAX_ROM_PATCHES];
+	int nRomPatches;
+
+	int gsaVersion;
+	uint32_t gsaSeeds[4];
+	int remainingAddresses;
 };
 
 struct GBACheatDevice {
@@ -82,6 +108,11 @@ void GBACheatInstallSet(struct GBACheatDevice*, struct GBACheatSet*);
 bool GBACheatAddCodeBreaker(struct GBACheatSet*, uint32_t op1, uint16_t op2);
 bool GBACheatAddCodeBreakerLine(struct GBACheatSet*, const char* line);
 
+bool GBACheatAddGameShark(struct GBACheatSet*, uint32_t op1, uint32_t op2);
+bool GBACheatAddGameSharkLine(struct GBACheatSet*, const char* line);
+
+bool GBACheatAddLine(struct GBACheatSet*, const char* line);
+
 void GBACheatRefresh(struct GBACheatDevice*);
 
 #endif
\ No newline at end of file
diff --git a/src/gba/supervisor/thread.c b/src/gba/supervisor/thread.c
index 7fdf4b390..5026fe62e 100644
--- a/src/gba/supervisor/thread.c
+++ b/src/gba/supervisor/thread.c
@@ -179,7 +179,7 @@ static THREAD_ENTRY _GBAThreadRun(void* context) {
 			if (!bytesRead) {
 				break;
 			}
-			GBACheatAddCodeBreakerLine(threadContext->cheats, cheat);
+			GBACheatAddLine(threadContext->cheats, cheat);
 		}
 	}
 	GBACheatInstallSet(&cheatDevice, threadContext->cheats);