diff --git a/src/gba/audio.c b/src/gba/audio.c
index 1b2d121e9..965e03c44 100644
--- a/src/gba/audio.c
+++ b/src/gba/audio.c
@@ -848,75 +848,84 @@ static void _sample(struct GBAAudio* audio) {
 }
 
 void GBAAudioSerialize(const struct GBAAudio* audio, struct GBASerializedState* state) {
-	state->audio.ch1Volume = audio->ch1.envelope.currentVolume;
-	state->audio.ch1Dead = audio->ch1.envelope.dead;
-	state->audio.ch1Hi = audio->ch1.control.hi;
-	state->audio.ch1.envelopeNextStep = audio->ch1.envelope.nextStep;
-	state->audio.ch1.waveNextStep = audio->ch1.control.nextStep;
-	state->audio.ch1.sweepNextStep = audio->ch1.nextSweep;
-	state->audio.ch1.endTime = audio->ch1.control.endTime;
-	state->audio.ch1.nextEvent = audio->nextCh1;
+	uint32_t flags = 0;
 
-	state->audio.ch2Volume = audio->ch2.envelope.currentVolume;
-	state->audio.ch2Dead = audio->ch2.envelope.dead;
-	state->audio.ch2Hi = audio->ch2.control.hi;
-	state->audio.ch2.envelopeNextStep = audio->ch2.envelope.nextStep;
-	state->audio.ch2.waveNextStep = audio->ch2.control.nextStep;
-	state->audio.ch2.endTime = audio->ch2.control.endTime;
-	state->audio.ch2.nextEvent = audio->nextCh2;
+	flags = GBASerializedAudioFlagsSetCh1Volume(flags, audio->ch1.envelope.currentVolume);
+	flags = GBASerializedAudioFlagsSetCh1Dead(flags, audio->ch1.envelope.dead);
+	flags = GBASerializedAudioFlagsSetCh1Hi(flags, audio->ch1.control.hi);
+	STORE_32(audio->ch1.envelope.nextStep, 0, &state->audio.ch1.envelopeNextStep);
+	STORE_32(audio->ch1.control.nextStep, 0, &state->audio.ch1.waveNextStep);
+	STORE_32(audio->ch1.nextSweep, 0, &state->audio.ch1.sweepNextStep);
+	STORE_32(audio->ch1.control.endTime, 0, &state->audio.ch1.endTime);
+	STORE_32(audio->nextCh1, 0, &state->audio.ch1.nextEvent);
+
+	flags = GBASerializedAudioFlagsSetCh2Volume(flags, audio->ch2.envelope.currentVolume);
+	flags = GBASerializedAudioFlagsSetCh2Dead(flags, audio->ch2.envelope.dead);
+	flags = GBASerializedAudioFlagsSetCh2Hi(flags, audio->ch2.control.hi);
+	STORE_32(audio->ch2.envelope.nextStep, 0, &state->audio.ch2.envelopeNextStep);
+	STORE_32(audio->ch2.control.nextStep, 0, &state->audio.ch2.waveNextStep);
+	STORE_32(audio->ch2.control.endTime, 0, &state->audio.ch2.endTime);
+	STORE_32(audio->nextCh2, 0, &state->audio.ch2.nextEvent);
 
 	memcpy(state->audio.ch3.wavebanks, audio->ch3.wavedata, sizeof(state->audio.ch3.wavebanks));
-	state->audio.ch3.endTime = audio->ch3.control.endTime;
-	state->audio.ch3.nextEvent = audio->nextCh3;
+	STORE_32(audio->ch3.control.endTime, 0, &state->audio.ch3.endTime);
+	STORE_32(audio->nextCh3, 0, &state->audio.ch3.nextEvent);
 
-	state->audio.ch4Volume = audio->ch4.envelope.currentVolume;
-	state->audio.ch4Dead = audio->ch4.envelope.dead;
-	state->audio.ch4.envelopeNextStep = audio->ch4.envelope.nextStep;
-	state->audio.ch4.lfsr = audio->ch4.lfsr;
-	state->audio.ch4.endTime = audio->ch4.control.endTime;
-	state->audio.ch4.nextEvent = audio->nextCh4;
+	state->audio.flags = GBASerializedAudioFlagsSetCh4Volume(flags, audio->ch4.envelope.currentVolume);
+	state->audio.flags = GBASerializedAudioFlagsSetCh4Dead(flags, audio->ch4.envelope.dead);
+	STORE_32(audio->ch4.envelope.nextStep, 0, &state->audio.ch4.envelopeNextStep);
+	STORE_32(audio->ch4.lfsr, 0, &state->audio.ch4.lfsr);
+	STORE_32(audio->ch4.control.endTime, 0, &state->audio.ch4.endTime);
+	STORE_32(audio->nextCh4, 0, &state->audio.ch4.nextEvent);
+
+	STORE_32(flags, 0, &state->audio.flags);
 
 	CircleBufferDump(&audio->chA.fifo, state->audio.fifoA, sizeof(state->audio.fifoA));
 	CircleBufferDump(&audio->chB.fifo, state->audio.fifoB, sizeof(state->audio.fifoB));
-	state->audio.fifoSize = CircleBufferSize(&audio->chA.fifo);
+	uint32_t fifoSize = CircleBufferSize(&audio->chA.fifo);
+	STORE_32(fifoSize, 0, &state->audio.fifoSize);
 
-	state->audio.nextEvent = audio->nextEvent;
-	state->audio.eventDiff = audio->eventDiff;
-	state->audio.nextSample = audio->nextSample;
+	STORE_32(audio->nextEvent, 0, &state->audio.nextEvent);
+	STORE_32(audio->eventDiff, 0, &state->audio.eventDiff);
+	STORE_32(audio->nextSample, 0, &state->audio.nextSample);
 }
 
 void GBAAudioDeserialize(struct GBAAudio* audio, const struct GBASerializedState* state) {
-	audio->ch1.envelope.currentVolume = state->audio.ch1Volume;
-	audio->ch1.envelope.dead = state->audio.ch1Dead;
-	audio->ch1.control.hi = state->audio.ch1Hi;
-	audio->ch1.envelope.nextStep = state->audio.ch1.envelopeNextStep;
-	audio->ch1.control.nextStep = state->audio.ch1.waveNextStep;
-	audio->ch1.nextSweep = state->audio.ch1.sweepNextStep;
-	audio->ch1.control.endTime = state->audio.ch1.endTime;
-	audio->nextCh1 = state->audio.ch1.nextEvent;
+	uint32_t flags;
+	LOAD_32(flags, 0, &state->audio.flags);
+	audio->ch1.envelope.currentVolume = GBASerializedAudioFlagsGetCh1Volume(flags);
+	audio->ch1.envelope.dead = GBASerializedAudioFlagsGetCh1Dead(flags);
+	audio->ch1.control.hi = GBASerializedAudioFlagsGetCh1Hi(flags);
+	LOAD_32(audio->ch1.envelope.nextStep, 0, &state->audio.ch1.envelopeNextStep);
+	LOAD_32(audio->ch1.control.nextStep, 0, &state->audio.ch1.waveNextStep);
+	LOAD_32(audio->ch1.nextSweep, 0, &state->audio.ch1.sweepNextStep);
+	LOAD_32(audio->ch1.control.endTime, 0, &state->audio.ch1.endTime);
+	LOAD_32(audio->nextCh1, 0, &state->audio.ch1.nextEvent);
 
-	audio->ch2.envelope.currentVolume = state->audio.ch2Volume;
-	audio->ch2.envelope.dead = state->audio.ch2Dead;
-	audio->ch2.control.hi = state->audio.ch2Hi;
-	audio->ch2.envelope.nextStep = state->audio.ch2.envelopeNextStep;
-	audio->ch2.control.nextStep = state->audio.ch2.waveNextStep;
-	audio->ch2.control.endTime = state->audio.ch2.endTime;
-	audio->nextCh2 = state->audio.ch2.nextEvent;
+	audio->ch2.envelope.currentVolume = GBASerializedAudioFlagsGetCh2Volume(flags);
+	audio->ch2.envelope.dead = GBASerializedAudioFlagsGetCh2Dead(flags);
+	audio->ch2.control.hi = GBASerializedAudioFlagsGetCh2Hi(flags);
+	LOAD_32(audio->ch2.envelope.nextStep, 0, &state->audio.ch2.envelopeNextStep);
+	LOAD_32(audio->ch2.control.nextStep, 0, &state->audio.ch2.waveNextStep);
+	LOAD_32(audio->ch2.control.endTime, 0, &state->audio.ch2.endTime);
+	LOAD_32(audio->nextCh2, 0, &state->audio.ch2.nextEvent);
 
+	// TODO: Big endian?
 	memcpy(audio->ch3.wavedata, state->audio.ch3.wavebanks, sizeof(audio->ch3.wavedata));
-	audio->ch3.control.endTime = state->audio.ch3.endTime;
-	audio->nextCh3 = state->audio.ch3.nextEvent;
+	LOAD_32(audio->ch3.control.endTime, 0, &state->audio.ch3.endTime);
+	LOAD_32(audio->nextCh3, 0, &state->audio.ch3.nextEvent);
 
-	audio->ch4.envelope.currentVolume = state->audio.ch4Volume;
-	audio->ch4.envelope.dead = state->audio.ch4Dead;
-	audio->ch4.envelope.nextStep = state->audio.ch4.envelopeNextStep;
-	audio->ch4.lfsr = state->audio.ch4.lfsr;
-	audio->ch4.control.endTime = state->audio.ch4.endTime;
-	audio->nextCh4 = state->audio.ch4.nextEvent;
+	audio->ch4.envelope.currentVolume = GBASerializedAudioFlagsGetCh4Volume(flags);
+	audio->ch4.envelope.dead = GBASerializedAudioFlagsGetCh4Dead(flags);
+	LOAD_32(audio->ch4.envelope.nextStep, 0, &state->audio.ch4.envelopeNextStep);
+	LOAD_32(audio->ch4.lfsr, 0, &state->audio.ch4.lfsr);
+	LOAD_32(audio->ch4.control.endTime, 0, &state->audio.ch4.endTime);
+	LOAD_32(audio->nextCh4, 0, &state->audio.ch4.nextEvent);
 
 	CircleBufferClear(&audio->chA.fifo);
 	CircleBufferClear(&audio->chB.fifo);
-	size_t fifoSize = state->audio.fifoSize;
+	uint32_t fifoSize;
+	LOAD_32(fifoSize, 0, &state->audio.fifoSize);
 	if (state->audio.fifoSize > CircleBufferCapacity(&audio->chA.fifo)) {
 		fifoSize = CircleBufferCapacity(&audio->chA.fifo);
 	}
@@ -926,9 +935,9 @@ void GBAAudioDeserialize(struct GBAAudio* audio, const struct GBASerializedState
 		CircleBufferWrite8(&audio->chB.fifo, state->audio.fifoB[i]);
 	}
 
-	audio->nextEvent = state->audio.nextEvent;
-	audio->eventDiff = state->audio.eventDiff;
-	audio->nextSample = state->audio.nextSample;
+	LOAD_32(audio->nextEvent, 0, &state->audio.nextEvent);
+	LOAD_32(audio->eventDiff, 0, &state->audio.eventDiff);
+	LOAD_32(audio->nextSample, 0, &state->audio.nextSample);
 }
 
 float GBAAudioCalculateRatio(float inputSampleRate, float desiredFPS, float desiredSampleRate) {
diff --git a/src/gba/audio.h b/src/gba/audio.h
index e236e01a3..31550b36a 100644
--- a/src/gba/audio.h
+++ b/src/gba/audio.h
@@ -128,7 +128,7 @@ struct GBAAudioChannel4 {
 		int32_t endTime;
 	} control;
 
-	unsigned lfsr;
+	uint32_t lfsr;
 	int8_t sample;
 };
 
diff --git a/src/gba/gba.c b/src/gba/gba.c
index 0b39e3f1a..ecb86f27a 100644
--- a/src/gba/gba.c
+++ b/src/gba/gba.c
@@ -252,7 +252,7 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 		struct GBATimer* nextTimer;
 
 		timer = &gba->timers[0];
-		if (timer->enable) {
+		if (GBATimerFlagsIsEnable(timer->flags)) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			while (timer->nextEvent <= 0) {
@@ -261,7 +261,7 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 				gba->memory.io[REG_TM0CNT_LO >> 1] = timer->reload;
 				timer->oldReload = timer->reload;
 
-				if (timer->doIrq) {
+				if (GBATimerFlagsIsDoIrq(timer->flags)) {
 					GBARaiseIRQ(gba, IRQ_TIMER0);
 				}
 
@@ -276,7 +276,7 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 				}
 
 				nextTimer = &gba->timers[1];
-				if (nextTimer->countUp) {
+				if (GBATimerFlagsIsCountUp(nextTimer->flags)) {
 					++gba->memory.io[REG_TM1CNT_LO >> 1];
 					if (!gba->memory.io[REG_TM1CNT_LO >> 1]) {
 						nextTimer->nextEvent = 0;
@@ -287,7 +287,7 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 		}
 
 		timer = &gba->timers[1];
-		if (timer->enable) {
+		if (GBATimerFlagsIsEnable(timer->flags)) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			if (timer->nextEvent <= 0) {
@@ -296,7 +296,7 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 				gba->memory.io[REG_TM1CNT_LO >> 1] = timer->reload;
 				timer->oldReload = timer->reload;
 
-				if (timer->doIrq) {
+				if (GBATimerFlagsIsDoIrq(timer->flags)) {
 					GBARaiseIRQ(gba, IRQ_TIMER1);
 				}
 
@@ -310,12 +310,12 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 					}
 				}
 
-				if (timer->countUp) {
+				if (GBATimerFlagsIsCountUp(timer->flags)) {
 					timer->nextEvent = INT_MAX;
 				}
 
 				nextTimer = &gba->timers[2];
-				if (nextTimer->countUp) {
+				if (GBATimerFlagsIsCountUp(nextTimer->flags)) {
 					++gba->memory.io[REG_TM2CNT_LO >> 1];
 					if (!gba->memory.io[REG_TM2CNT_LO >> 1]) {
 						nextTimer->nextEvent = 0;
@@ -328,7 +328,7 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 		}
 
 		timer = &gba->timers[2];
-		if (timer->enable) {
+		if (GBATimerFlagsIsEnable(timer->flags)) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			if (timer->nextEvent <= 0) {
@@ -337,16 +337,16 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 				gba->memory.io[REG_TM2CNT_LO >> 1] = timer->reload;
 				timer->oldReload = timer->reload;
 
-				if (timer->doIrq) {
+				if (GBATimerFlagsIsDoIrq(timer->flags)) {
 					GBARaiseIRQ(gba, IRQ_TIMER2);
 				}
 
-				if (timer->countUp) {
+				if (GBATimerFlagsIsCountUp(timer->flags)) {
 					timer->nextEvent = INT_MAX;
 				}
 
 				nextTimer = &gba->timers[3];
-				if (nextTimer->countUp) {
+				if (GBATimerFlagsIsCountUp(nextTimer->flags)) {
 					++gba->memory.io[REG_TM3CNT_LO >> 1];
 					if (!gba->memory.io[REG_TM3CNT_LO >> 1]) {
 						nextTimer->nextEvent = 0;
@@ -359,7 +359,7 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 		}
 
 		timer = &gba->timers[3];
-		if (timer->enable) {
+		if (GBATimerFlagsIsEnable(timer->flags)) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			if (timer->nextEvent <= 0) {
@@ -368,11 +368,11 @@ static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
 				gba->memory.io[REG_TM3CNT_LO >> 1] = timer->reload;
 				timer->oldReload = timer->reload;
 
-				if (timer->doIrq) {
+				if (GBATimerFlagsIsDoIrq(timer->flags)) {
 					GBARaiseIRQ(gba, IRQ_TIMER3);
 				}
 
-				if (timer->countUp) {
+				if (GBATimerFlagsIsCountUp(timer->flags)) {
 					timer->nextEvent = INT_MAX;
 				}
 			}
@@ -481,47 +481,47 @@ void GBAApplyPatch(struct GBA* gba, struct Patch* patch) {
 
 void GBATimerUpdateRegister(struct GBA* gba, int timer) {
 	struct GBATimer* currentTimer = &gba->timers[timer];
-	if (currentTimer->enable && !currentTimer->countUp) {
+	if (GBATimerFlagsIsEnable(currentTimer->flags) && !GBATimerFlagsIsCountUp(currentTimer->flags)) {
 		int32_t prefetchSkew = 0;
 		if (gba->memory.lastPrefetchedPc - gba->memory.lastPrefetchedLoads * WORD_SIZE_THUMB >= (uint32_t) gba->cpu->gprs[ARM_PC]) {
 			prefetchSkew = (gba->memory.lastPrefetchedPc - gba->cpu->gprs[ARM_PC]) * (gba->cpu->memory.activeSeqCycles16 + 1) / WORD_SIZE_THUMB;
 		}
 		// Reading this takes two cycles (1N+1I), so let's remove them preemptively
-		gba->memory.io[(REG_TM0CNT_LO + (timer << 2)) >> 1] = currentTimer->oldReload + ((gba->cpu->cycles - currentTimer->lastEvent - 2 + prefetchSkew) >> currentTimer->prescaleBits);
+		gba->memory.io[(REG_TM0CNT_LO + (timer << 2)) >> 1] = currentTimer->oldReload + ((gba->cpu->cycles - currentTimer->lastEvent - 2 + prefetchSkew) >> GBATimerFlagsGetPrescaleBits(currentTimer->flags));
 	}
 }
 
 void GBATimerWriteTMCNT_LO(struct GBA* gba, int timer, uint16_t reload) {
 	gba->timers[timer].reload = reload;
-	gba->timers[timer].overflowInterval = (0x10000 - gba->timers[timer].reload) << gba->timers[timer].prescaleBits;
+	gba->timers[timer].overflowInterval = (0x10000 - gba->timers[timer].reload) << GBATimerFlagsGetPrescaleBits(gba->timers[timer].flags);
 }
 
 void GBATimerWriteTMCNT_HI(struct GBA* gba, int timer, uint16_t control) {
 	struct GBATimer* currentTimer = &gba->timers[timer];
 	GBATimerUpdateRegister(gba, timer);
 
-	int oldPrescale = currentTimer->prescaleBits;
+	unsigned oldPrescale = GBATimerFlagsGetPrescaleBits(currentTimer->flags);
 	switch (control & 0x0003) {
 	case 0x0000:
-		currentTimer->prescaleBits = 0;
+		currentTimer->flags = GBATimerFlagsSetPrescaleBits(currentTimer->flags, 0);
 		break;
 	case 0x0001:
-		currentTimer->prescaleBits = 6;
+		currentTimer->flags = GBATimerFlagsSetPrescaleBits(currentTimer->flags, 6);
 		break;
 	case 0x0002:
-		currentTimer->prescaleBits = 8;
+		currentTimer->flags = GBATimerFlagsSetPrescaleBits(currentTimer->flags, 8);
 		break;
 	case 0x0003:
-		currentTimer->prescaleBits = 10;
+		currentTimer->flags = GBATimerFlagsSetPrescaleBits(currentTimer->flags, 10);
 		break;
 	}
-	currentTimer->countUp = !!(control & 0x0004);
-	currentTimer->doIrq = !!(control & 0x0040);
-	currentTimer->overflowInterval = (0x10000 - currentTimer->reload) << currentTimer->prescaleBits;
-	int wasEnabled = currentTimer->enable;
-	currentTimer->enable = !!(control & 0x0080);
-	if (!wasEnabled && currentTimer->enable) {
-		if (!currentTimer->countUp) {
+	currentTimer->flags = GBATimerFlagsTestFillCountUp(currentTimer->flags, control & 0x0004);
+	currentTimer->flags = GBATimerFlagsTestFillDoIrq(currentTimer->flags, control & 0x0040);
+	currentTimer->overflowInterval = (0x10000 - currentTimer->reload) << GBATimerFlagsGetPrescaleBits(currentTimer->flags);
+	bool wasEnabled = GBATimerFlagsIsEnable(currentTimer->flags);
+	currentTimer->flags = GBATimerFlagsTestFillEnable(currentTimer->flags, control & 0x0080);
+	if (!wasEnabled && GBATimerFlagsIsEnable(currentTimer->flags)) {
+		if (!GBATimerFlagsIsCountUp(currentTimer->flags)) {
 			currentTimer->nextEvent = gba->cpu->cycles + currentTimer->overflowInterval;
 		} else {
 			currentTimer->nextEvent = INT_MAX;
@@ -530,12 +530,12 @@ void GBATimerWriteTMCNT_HI(struct GBA* gba, int timer, uint16_t control) {
 		currentTimer->oldReload = currentTimer->reload;
 		currentTimer->lastEvent = gba->cpu->cycles;
 		gba->timersEnabled |= 1 << timer;
-	} else if (wasEnabled && !currentTimer->enable) {
-		if (!currentTimer->countUp) {
+	} else if (wasEnabled && !GBATimerFlagsIsEnable(currentTimer->flags)) {
+		if (!GBATimerFlagsIsCountUp(currentTimer->flags)) {
 			gba->memory.io[(REG_TM0CNT_LO + (timer << 2)) >> 1] = currentTimer->oldReload + ((gba->cpu->cycles - currentTimer->lastEvent) >> oldPrescale);
 		}
 		gba->timersEnabled &= ~(1 << timer);
-	} else if (currentTimer->prescaleBits != oldPrescale && !currentTimer->countUp) {
+	} else if (GBATimerFlagsGetPrescaleBits(currentTimer->flags) != oldPrescale && !GBATimerFlagsIsCountUp(currentTimer->flags)) {
 		// FIXME: this might be before present
 		currentTimer->nextEvent = currentTimer->lastEvent + currentTimer->overflowInterval;
 	}
diff --git a/src/gba/gba.h b/src/gba/gba.h
index f4f89e5dd..d3281e22b 100644
--- a/src/gba/gba.h
+++ b/src/gba/gba.h
@@ -59,16 +59,19 @@ struct GBAThread;
 struct Patch;
 struct VFile;
 
+DECL_BITFIELD(GBATimerFlags, uint32_t);
+DECL_BITS(GBATimerFlags, PrescaleBits, 0, 4);
+DECL_BIT(GBATimerFlags, CountUp, 4);
+DECL_BIT(GBATimerFlags, DoIrq, 5);
+DECL_BIT(GBATimerFlags, Enable, 6);
+
 struct GBATimer {
 	uint16_t reload;
 	uint16_t oldReload;
 	int32_t lastEvent;
 	int32_t nextEvent;
 	int32_t overflowInterval;
-	unsigned prescaleBits : 4;
-	unsigned countUp : 1;
-	unsigned doIrq : 1;
-	unsigned enable : 1;
+	GBATimerFlags flags;
 };
 
 struct GBA {
diff --git a/src/gba/gui/gui-runner.c b/src/gba/gui/gui-runner.c
index d169a5c79..11b0ef761 100644
--- a/src/gba/gui/gui-runner.c
+++ b/src/gba/gui/gui-runner.c
@@ -156,8 +156,6 @@ void GBAGUIRunloop(struct GBAGUIRunner* runner) {
 	GUIMenuItemListInit(&stateSaveMenu.items, 9);
 	GUIMenuItemListInit(&stateLoadMenu.items, 9);
 	*GUIMenuItemListAppend(&pauseMenu.items) = (struct GUIMenuItem) { .title = "Unpause", .data = (void*) RUNNER_CONTINUE };
-#if !(defined(__POWERPC__) || defined(__PPC__))
-	// PPC doesn't have working savestates yet
 	*GUIMenuItemListAppend(&pauseMenu.items) = (struct GUIMenuItem) { .title = "Save state", .submenu = &stateSaveMenu };
 	*GUIMenuItemListAppend(&pauseMenu.items) = (struct GUIMenuItem) { .title = "Load state", .submenu = &stateLoadMenu };
 
@@ -180,7 +178,7 @@ void GBAGUIRunloop(struct GBAGUIRunner* runner) {
 	*GUIMenuItemListAppend(&stateLoadMenu.items) = (struct GUIMenuItem) { .title = "State 7", .data = (void*) (RUNNER_LOAD_STATE | RUNNER_STATE_7) };
 	*GUIMenuItemListAppend(&stateLoadMenu.items) = (struct GUIMenuItem) { .title = "State 8", .data = (void*) (RUNNER_LOAD_STATE | RUNNER_STATE_8) };
 	*GUIMenuItemListAppend(&stateLoadMenu.items) = (struct GUIMenuItem) { .title = "State 9", .data = (void*) (RUNNER_LOAD_STATE | RUNNER_STATE_9) };
-#endif
+
 	*GUIMenuItemListAppend(&pauseMenu.items) = (struct GUIMenuItem) { .title = "Take screenshot", .data = (void*) RUNNER_SCREENSHOT };
 	*GUIMenuItemListAppend(&pauseMenu.items) = (struct GUIMenuItem) { .title = "Configure", .data = (void*) RUNNER_CONFIG };
 	*GUIMenuItemListAppend(&pauseMenu.items) = (struct GUIMenuItem) { .title = "Exit game", .data = (void*) RUNNER_EXIT };
diff --git a/src/gba/hardware.c b/src/gba/hardware.c
index af0a6a283..07463920f 100644
--- a/src/gba/hardware.c
+++ b/src/gba/hardware.c
@@ -591,41 +591,65 @@ int32_t _gbpSioProcessEvents(struct GBASIODriver* driver, int32_t cycles) {
 // == Serialization
 
 void GBAHardwareSerialize(const struct GBACartridgeHardware* hw, struct GBASerializedState* state) {
-	state->hw.readWrite = hw->readWrite;
-	state->hw.pinState = hw->pinState;
-	state->hw.pinDirection = hw->direction;
+	GBASerializedHWFlags1 flags1 = 0;
+	GBASerializedHWFlags2 flags2 = 0;
+	flags1 = GBASerializedHWFlags1SetReadWrite(flags1, hw->readWrite);
+	STORE_16(hw->pinState, 0, &state->hw.pinState);
+	STORE_16(hw->direction, 0, &state->hw.pinDirection);
 	state->hw.devices = hw->devices;
-	state->hw.rtc = hw->rtc;
-	state->hw.gyroSample = hw->gyroSample;
-	state->hw.gyroEdge = hw->gyroEdge;
-	state->hw.tiltSampleX = hw->tiltX;
-	state->hw.tiltSampleY = hw->tiltY;
-	state->hw.tiltState = hw->tiltState;
-	state->hw.lightCounter = hw->lightCounter;
+
+	STORE_32(hw->rtc.bytesRemaining, 0, &state->hw.rtc.bytesRemaining);
+	STORE_32(hw->rtc.transferStep, 0, &state->hw.rtc.transferStep);
+	STORE_32(hw->rtc.bitsRead, 0, &state->hw.rtc.bitsRead);
+	STORE_32(hw->rtc.bits, 0, &state->hw.rtc.bits);
+	STORE_32(hw->rtc.commandActive, 0, &state->hw.rtc.commandActive);
+	STORE_32(hw->rtc.command, 0, &state->hw.rtc.command);
+	STORE_32(hw->rtc.control, 0, &state->hw.rtc.control);
+	memcpy(state->hw.rtc.time, hw->rtc.time, sizeof(state->hw.rtc.time));
+
+	STORE_16(hw->gyroSample, 0, &state->hw.gyroSample);
+	flags1 = GBASerializedHWFlags1SetGyroEdge(flags1, hw->gyroEdge);
+	STORE_16(hw->tiltX, 0, &state->hw.tiltSampleX);
+	STORE_16(hw->tiltY, 0, &state->hw.tiltSampleY);
+	flags2 = GBASerializedHWFlags2SetTiltState(flags2, hw->tiltState);
+	flags2 = GBASerializedHWFlags1SetLightCounter(flags2, hw->lightCounter);
 	state->hw.lightSample = hw->lightSample;
-	state->hw.lightEdge = hw->lightEdge;
-	state->hw.gbpInputsPosted = hw->gbpInputsPosted;
-	state->hw.gbpTxPosition = hw->gbpTxPosition;
-	state->hw.gbpNextEvent = hw->gbpNextEvent;
+	flags1 = GBASerializedHWFlags1SetLightEdge(flags1, hw->lightEdge);
+	flags2 = GBASerializedHWFlags2SetGbpInputsPosted(flags2, hw->gbpInputsPosted);
+	flags2 = GBASerializedHWFlags2SetGbpTxPosition(flags2, hw->gbpTxPosition);
+	STORE_32(hw->gbpNextEvent, 0, &state->hw.gbpNextEvent);
+	STORE_32(flags1, 0, &state->hw.flags1);
+	STORE_32(flags2, 0, &state->hw.flags2);
 }
 
 void GBAHardwareDeserialize(struct GBACartridgeHardware* hw, const struct GBASerializedState* state) {
-	hw->readWrite = state->hw.readWrite;
-	hw->pinState = state->hw.pinState;
-	hw->direction = state->hw.pinDirection;
+	GBASerializedHWFlags1 flags1;
+	LOAD_16(flags1, 0, &state->hw.flags1);
+	hw->readWrite = GBASerializedHWFlags1GetReadWrite(flags1);
+	LOAD_16(hw->pinState, 0, &state->hw.pinState);
+	LOAD_16(hw->direction, 0, &state->hw.pinDirection);
 	hw->devices = state->hw.devices;
-	hw->rtc = state->hw.rtc;
-	hw->gyroSample = state->hw.gyroSample;
-	hw->gyroEdge = state->hw.gyroEdge;
-	hw->tiltX = state->hw.tiltSampleX;
-	hw->tiltY = state->hw.tiltSampleY;
-	hw->tiltState = state->hw.tiltState;
-	hw->lightCounter = state->hw.lightCounter;
+
+	LOAD_32(hw->rtc.bytesRemaining, 0, &state->hw.rtc.bytesRemaining);
+	LOAD_32(hw->rtc.transferStep, 0, &state->hw.rtc.transferStep);
+	LOAD_32(hw->rtc.bitsRead, 0, &state->hw.rtc.bitsRead);
+	LOAD_32(hw->rtc.bits, 0, &state->hw.rtc.bits);
+	LOAD_32(hw->rtc.commandActive, 0, &state->hw.rtc.commandActive);
+	LOAD_32(hw->rtc.command, 0, &state->hw.rtc.command);
+	LOAD_32(hw->rtc.control, 0, &state->hw.rtc.control);
+	memcpy(hw->rtc.time, state->hw.rtc.time, sizeof(hw->rtc.time));
+
+	LOAD_16(hw->gyroSample, 0, &state->hw.gyroSample);
+	hw->gyroEdge = GBASerializedHWFlags1GetGyroEdge(flags1);
+	LOAD_16(hw->tiltX, 0, &state->hw.tiltSampleX);
+	LOAD_16(hw->tiltY, 0, &state->hw.tiltSampleY);
+	hw->tiltState = GBASerializedHWFlags2GetTiltState(state->hw.flags2);
+	hw->lightCounter = GBASerializedHWFlags1GetLightCounter(flags1);
 	hw->lightSample = state->hw.lightSample;
-	hw->lightEdge = state->hw.lightEdge;
-	hw->gbpInputsPosted = state->hw.gbpInputsPosted;
-	hw->gbpTxPosition = state->hw.gbpTxPosition;
-	hw->gbpNextEvent = state->hw.gbpNextEvent;
+	hw->lightEdge = GBASerializedHWFlags1GetLightEdge(flags1);
+	hw->gbpInputsPosted = GBASerializedHWFlags2GetGbpInputsPosted(state->hw.flags2);
+	hw->gbpTxPosition = GBASerializedHWFlags2GetGbpTxPosition(state->hw.flags2);
+	LOAD_32(hw->gbpNextEvent, 0, &state->hw.gbpNextEvent);
 	if (hw->devices & HW_GB_PLAYER) {
 		GBASIOSetDriver(&hw->p->sio, &hw->gbpDriver.d, SIO_NORMAL_32);
 	}
diff --git a/src/gba/hardware.h b/src/gba/hardware.h
index 7923d0669..fa64a9075 100644
--- a/src/gba/hardware.h
+++ b/src/gba/hardware.h
@@ -98,7 +98,7 @@ DECL_BITFIELD(GPIOPin, uint16_t);
 
 struct GBACartridgeHardware {
 	struct GBA* p;
-	int devices;
+	uint32_t devices;
 	enum GPIODirection readWrite;
 	uint16_t* gpioBase;
 
diff --git a/src/gba/io.c b/src/gba/io.c
index 04fd8ca7b..02652a238 100644
--- a/src/gba/io.c
+++ b/src/gba/io.c
@@ -690,21 +690,27 @@ void GBAIOSerialize(struct GBA* gba, struct GBASerializedState* state) {
 	int i;
 	for (i = 0; i < REG_MAX; i += 2) {
 		if (_isSpecialRegister[i >> 1]) {
-			state->io[i >> 1] = gba->memory.io[i >> 1];
+			STORE_16(gba->memory.io[i >> 1], i, state->io);
 		} else if (_isValidRegister[i >> 1]) {
-			state->io[i >> 1] = GBAIORead(gba, i);
+			uint16_t reg = GBAIORead(gba, i);
+			STORE_16(reg, i, state->io);
 		}
 	}
 
 	for (i = 0; i < 4; ++i) {
-		state->io[(REG_DMA0CNT_LO + i * 12) >> 1] = gba->memory.io[(REG_DMA0CNT_LO + i * 12) >> 1];
-		state->dma[i].nextSource = gba->memory.dma[i].nextSource;
-		state->dma[i].nextDest = gba->memory.dma[i].nextDest;
-		state->dma[i].nextCount = gba->memory.dma[i].nextCount;
-		state->dma[i].nextEvent = gba->memory.dma[i].nextEvent;
+		STORE_16(gba->memory.io[(REG_DMA0CNT_LO + i * 12) >> 1], (REG_DMA0CNT_LO + i * 12), state->io);
+		STORE_16(gba->timers[i].reload, 0, &state->timers[i].reload);
+		STORE_16(gba->timers[i].oldReload, 0, &state->timers[i].oldReload);
+		STORE_32(gba->timers[i].lastEvent, 0, &state->timers[i].lastEvent);
+		STORE_32(gba->timers[i].nextEvent, 0, &state->timers[i].nextEvent);
+		STORE_32(gba->timers[i].overflowInterval, 0, &state->timers[i].overflowInterval);
+		STORE_32(gba->timers[i].flags, 0, &state->timers[i].flags);
+		STORE_32(gba->memory.dma[i].nextSource, 0, &state->dma[i].nextSource);
+		STORE_32(gba->memory.dma[i].nextDest, 0, &state->dma[i].nextDest);
+		STORE_32(gba->memory.dma[i].nextCount, 0, &state->dma[i].nextCount);
+		STORE_32(gba->memory.dma[i].nextEvent, 0, &state->dma[i].nextEvent);
 	}
 
-	memcpy(state->timers, gba->timers, sizeof(state->timers));
 	GBAHardwareSerialize(&gba->memory.hw, state);
 }
 
@@ -712,25 +718,32 @@ void GBAIODeserialize(struct GBA* gba, const struct GBASerializedState* state) {
 	int i;
 	for (i = 0; i < REG_MAX; i += 2) {
 		if (_isSpecialRegister[i >> 1]) {
-			gba->memory.io[i >> 1] = state->io[i >> 1];
+			LOAD_16(gba->memory.io[i >> 1], i, state->io);
 		} else if (_isValidRegister[i >> 1]) {
-			GBAIOWrite(gba, i, state->io[i >> 1]);
+			uint16_t reg;
+			LOAD_16(reg, i, state->io);
+			GBAIOWrite(gba, i, reg);
 		}
 	}
 
 	gba->timersEnabled = 0;
-	memcpy(gba->timers, state->timers, sizeof(gba->timers));
 	for (i = 0; i < 4; ++i) {
-		gba->memory.dma[i].reg = state->io[(REG_DMA0CNT_HI + i * 12) >> 1];
-		gba->memory.dma[i].nextSource = state->dma[i].nextSource;
-		gba->memory.dma[i].nextDest = state->dma[i].nextDest;
-		gba->memory.dma[i].nextCount = state->dma[i].nextCount;
-		gba->memory.dma[i].nextEvent = state->dma[i].nextEvent;
+		LOAD_16(gba->timers[i].reload, 0, &state->timers[i].reload);
+		LOAD_16(gba->timers[i].oldReload, 0, &state->timers[i].oldReload);
+		LOAD_32(gba->timers[i].lastEvent, 0, &state->timers[i].lastEvent);
+		LOAD_32(gba->timers[i].nextEvent, 0, &state->timers[i].nextEvent);
+		LOAD_32(gba->timers[i].overflowInterval, 0, &state->timers[i].overflowInterval);
+		LOAD_32(gba->timers[i].flags, 0, &state->timers[i].flags);
+		LOAD_16(gba->memory.dma[i].reg, (REG_DMA0CNT_HI + i * 12), state->io);
+		LOAD_32(gba->memory.dma[i].nextSource, 0, &state->dma[i].nextSource);
+		LOAD_32(gba->memory.dma[i].nextDest, 0, &state->dma[i].nextDest);
+		LOAD_32(gba->memory.dma[i].nextCount, 0, &state->dma[i].nextCount);
+		LOAD_32(gba->memory.dma[i].nextEvent, 0, &state->dma[i].nextEvent);
 		if (GBADMARegisterGetTiming(gba->memory.dma[i].reg) != DMA_TIMING_NOW) {
 			GBAMemoryScheduleDMA(gba, i, &gba->memory.dma[i]);
 		}
 
-		if (gba->timers[i].enable) {
+		if (GBATimerFlagsIsEnable(gba->timers[i].flags)) {
 			gba->timersEnabled |= 1 << i;
 		}
 	}
diff --git a/src/gba/savedata.c b/src/gba/savedata.c
index daa8aca68..de535aea1 100644
--- a/src/gba/savedata.c
+++ b/src/gba/savedata.c
@@ -444,13 +444,15 @@ void GBASavedataClean(struct GBASavedata* savedata, uint32_t frameCount) {
 void GBASavedataSerialize(const struct GBASavedata* savedata, struct GBASerializedState* state, bool includeData) {
 	state->savedata.type = savedata->type;
 	state->savedata.command = savedata->command;
-	state->savedata.flashState = savedata->flashState;
-	state->savedata.flashBank = savedata->currentBank == &savedata->data[0x10000];
-	state->savedata.readBitsRemaining = savedata->readBitsRemaining;
-	state->savedata.readAddress = savedata->readAddress;
-	state->savedata.writeAddress = savedata->writeAddress;
-	state->savedata.settlingSector = savedata->settling;
-	state->savedata.settlingDust = savedata->dust;
+	GBASerializedSavedataFlags flags = 0;
+	flags = GBASerializedSavedataFlagsSetFlashState(flags, savedata->flashState);
+	flags = GBASerializedSavedataFlagsTestFillFlashBank(flags, savedata->currentBank == &savedata->data[0x10000]);
+	state->savedata.flags = flags;
+	STORE_32(savedata->readBitsRemaining, 0, &state->savedata.readBitsRemaining);
+	STORE_32(savedata->readAddress, 0, &state->savedata.readAddress);
+	STORE_32(savedata->writeAddress, 0, &state->savedata.writeAddress);
+	STORE_16(savedata->settling, 0, &state->savedata.settlingSector);
+	STORE_16(savedata->dust, 0, &state->savedata.settlingDust);
 
 	UNUSED(includeData); // TODO
 }
@@ -463,15 +465,16 @@ void GBASavedataDeserialize(struct GBASavedata* savedata, const struct GBASerial
 		GBASavedataForceType(savedata, state->savedata.type, savedata->realisticTiming);
 	}
 	savedata->command = state->savedata.command;
-	savedata->flashState = state->savedata.flashState;
-	savedata->readBitsRemaining = state->savedata.readBitsRemaining;
-	savedata->readAddress = state->savedata.readAddress;
-	savedata->writeAddress = state->savedata.writeAddress;
-	savedata->settling = state->savedata.settlingSector;
-	savedata->dust = state->savedata.settlingDust;
+	GBASerializedSavedataFlags flags = state->savedata.flags;
+	savedata->flashState = GBASerializedSavedataFlagsGetFlashState(flags);
+	LOAD_32(savedata->readBitsRemaining, 0, &state->savedata.readBitsRemaining);
+	LOAD_32(savedata->readAddress, 0, &state->savedata.readAddress);
+	LOAD_32(savedata->writeAddress, 0, &state->savedata.writeAddress);
+	LOAD_16(savedata->settling, 0, &state->savedata.settlingSector);
+	LOAD_16(savedata->dust, 0, &state->savedata.settlingDust);
 
 	if (savedata->type == SAVEDATA_FLASH1M) {
-		_flashSwitchBank(savedata, state->savedata.flashBank);
+		_flashSwitchBank(savedata, GBASerializedSavedataFlagsGetFlashBank(flags));
 	}
 
 	UNUSED(includeData); // TODO
diff --git a/src/gba/serialize.c b/src/gba/serialize.c
index c7fa7b016..3dd29c298 100644
--- a/src/gba/serialize.c
+++ b/src/gba/serialize.c
@@ -25,9 +25,9 @@
 const uint32_t GBA_SAVESTATE_MAGIC = 0x01000000;
 
 void GBASerialize(struct GBA* gba, struct GBASerializedState* state) {
-	state->versionMagic = GBA_SAVESTATE_MAGIC;
-	state->biosChecksum = gba->biosChecksum;
-	state->romCrc32 = gba->romCrc32;
+	STORE_32(GBA_SAVESTATE_MAGIC, 0, &state->versionMagic);
+	STORE_32(gba->biosChecksum, 0, &state->biosChecksum);
+	STORE_32(gba->romCrc32, 0, &state->romCrc32);
 
 	if (gba->memory.rom) {
 		state->id = ((struct GBACartridge*) gba->memory.rom)->id;
@@ -37,17 +37,25 @@ void GBASerialize(struct GBA* gba, struct GBASerializedState* state) {
 		memset(state->title, 0, sizeof(state->title));
 	}
 
-	memcpy(state->cpu.gprs, gba->cpu->gprs, sizeof(state->cpu.gprs));
-	state->cpu.cpsr = gba->cpu->cpsr;
-	state->cpu.spsr = gba->cpu->spsr;
-	state->cpu.cycles = gba->cpu->cycles;
-	state->cpu.nextEvent = gba->cpu->nextEvent;
-	memcpy(state->cpu.bankedRegisters, gba->cpu->bankedRegisters, 6 * 7 * sizeof(int32_t));
-	memcpy(state->cpu.bankedSPSRs, gba->cpu->bankedSPSRs, 6 * sizeof(int32_t));
+	int i;
+	for (i = 0; i < 16; ++i) {
+		STORE_32(gba->cpu->gprs[i], i * sizeof(state->cpu.gprs[0]), state->cpu.gprs);
+	}
+	STORE_32(gba->cpu->cpsr.packed, 0, &state->cpu.cpsr.packed);
+	STORE_32(gba->cpu->spsr.packed, 0, &state->cpu.spsr.packed);
+	STORE_32(gba->cpu->cycles, 0, &state->cpu.cycles);
+	STORE_32(gba->cpu->nextEvent, 0, &state->cpu.nextEvent);
+	for (i = 0; i < 6; ++i) {
+		int j;
+		for (j = 0; j < 7; ++j) {
+			STORE_32(gba->cpu->bankedRegisters[i][j], (i * 7 + j) * sizeof(gba->cpu->bankedRegisters[0][0]), state->cpu.bankedRegisters);
+		}
+		STORE_32(gba->cpu->bankedSPSRs[i], i * sizeof(gba->cpu->bankedSPSRs[0]), state->cpu.bankedSPSRs);
+	}
 
 	state->biosPrefetch = gba->memory.biosPrefetch;
-	state->cpuPrefetch[0] = gba->cpu->prefetch[0];
-	state->cpuPrefetch[1] = gba->cpu->prefetch[1];
+	STORE_32(gba->cpu->prefetch[0], 0, state->cpuPrefetch);
+	STORE_32(gba->cpu->prefetch[1], 4, state->cpuPrefetch);
 
 	GBAMemorySerialize(&gba->memory, state);
 	GBAIOSerialize(gba, state);
@@ -63,13 +71,19 @@ void GBASerialize(struct GBA* gba, struct GBASerializedState* state) {
 
 bool GBADeserialize(struct GBA* gba, const struct GBASerializedState* state) {
 	bool error = false;
-	if (state->versionMagic != GBA_SAVESTATE_MAGIC) {
-		GBALog(gba, GBA_LOG_WARN, "Invalid or too new savestate");
+	int32_t check;
+	uint32_t ucheck;
+	LOAD_32(ucheck, 0, &state->versionMagic);
+	if (ucheck != GBA_SAVESTATE_MAGIC) {
+		GBALog(gba, GBA_LOG_WARN, "Invalid or too new savestate: expected %08X, got %08X", GBA_SAVESTATE_MAGIC, ucheck);
 		error = true;
 	}
-	if (state->biosChecksum != gba->biosChecksum) {
-		GBALog(gba, GBA_LOG_WARN, "Savestate created using a different version of the BIOS");
-		if (state->cpu.gprs[ARM_PC] < SIZE_BIOS && state->cpu.gprs[ARM_PC] >= 0x20) {
+	LOAD_32(ucheck, 0, &state->biosChecksum);
+	if (ucheck != gba->biosChecksum) {
+		GBALog(gba, GBA_LOG_WARN, "Savestate created using a different version of the BIOS: expected %08X, got %08X", gba->biosChecksum, ucheck);
+		uint32_t pc;
+		LOAD_32(pc, ARM_PC * sizeof(state->cpu.gprs[0]), state->cpu.gprs);
+		if (pc < SIZE_BIOS && pc >= 0x20) {
 			error = true;
 		}
 	}
@@ -80,46 +94,60 @@ bool GBADeserialize(struct GBA* gba, const struct GBASerializedState* state) {
 		GBALog(gba, GBA_LOG_WARN, "Savestate is for a game, but no game loaded");
 		error = true;
 	}
-	if (state->romCrc32 != gba->romCrc32) {
+	LOAD_32(ucheck, 0, &state->romCrc32);
+	if (ucheck != gba->romCrc32) {
 		GBALog(gba, GBA_LOG_WARN, "Savestate is for a different version of the game");
 	}
-	if (state->cpu.cycles < 0) {
+	LOAD_32(check, 0, &state->cpu.cycles);
+	if (check < 0) {
 		GBALog(gba, GBA_LOG_WARN, "Savestate is corrupted: CPU cycles are negative");
 		error = true;
 	}
-	if (state->cpu.cycles >= (int32_t) GBA_ARM7TDMI_FREQUENCY) {
+	if (check >= (int32_t) GBA_ARM7TDMI_FREQUENCY) {
 		GBALog(gba, GBA_LOG_WARN, "Savestate is corrupted: CPU cycles are too high");
 		error = true;
 	}
-	if (state->video.eventDiff < 0) {
+	LOAD_32(check, 0, &state->video.eventDiff);
+	if (check < 0) {
 		GBALog(gba, GBA_LOG_WARN, "Savestate is corrupted: video eventDiff is negative");
 		error = true;
 	}
-	int region = (state->cpu.gprs[ARM_PC] >> BASE_OFFSET);
-	if ((region == REGION_CART0 || region == REGION_CART1 || region == REGION_CART2) && ((state->cpu.gprs[ARM_PC] - WORD_SIZE_ARM) & SIZE_CART0) >= gba->memory.romSize - WORD_SIZE_ARM) {
+	LOAD_32(check, ARM_PC * sizeof(state->cpu.gprs[0]), state->cpu.gprs);
+	int region = (check >> BASE_OFFSET);
+	if ((region == REGION_CART0 || region == REGION_CART1 || region == REGION_CART2) && ((check - WORD_SIZE_ARM) & SIZE_CART0) >= gba->memory.romSize - WORD_SIZE_ARM) {
 		GBALog(gba, GBA_LOG_WARN, "Savestate created using a differently sized version of the ROM");
 		error = true;
 	}
 	if (error) {
 		return false;
 	}
-	memcpy(gba->cpu->gprs, state->cpu.gprs, sizeof(gba->cpu->gprs));
-	gba->cpu->cpsr = state->cpu.cpsr;
-	gba->cpu->spsr = state->cpu.spsr;
-	gba->cpu->cycles = state->cpu.cycles;
-	gba->cpu->nextEvent = state->cpu.nextEvent;
-	memcpy(gba->cpu->bankedRegisters, state->cpu.bankedRegisters, 6 * 7 * sizeof(int32_t));
-	memcpy(gba->cpu->bankedSPSRs, state->cpu.bankedSPSRs, 6 * sizeof(int32_t));
+	size_t i;
+	for (i = 0; i < 16; ++i) {
+		LOAD_32(gba->cpu->gprs[i], i * sizeof(gba->cpu->gprs[0]), state->cpu.gprs);
+	}
+	LOAD_32(gba->cpu->cpsr.packed, 0, &state->cpu.cpsr.packed);
+	LOAD_32(gba->cpu->spsr.packed, 0, &state->cpu.spsr.packed);
+	LOAD_32(gba->cpu->cycles, 0, &state->cpu.cycles);
+	LOAD_32(gba->cpu->nextEvent, 0, &state->cpu.nextEvent);
+	for (i = 0; i < 6; ++i) {
+		int j;
+		for (j = 0; j < 7; ++j) {
+			LOAD_32(gba->cpu->bankedRegisters[i][j], (i * 7 + j) * sizeof(gba->cpu->bankedRegisters[0][0]), state->cpu.bankedRegisters);
+		}
+		LOAD_32(gba->cpu->bankedSPSRs[i], i * sizeof(gba->cpu->bankedSPSRs[0]), state->cpu.bankedSPSRs);
+	}
 	gba->cpu->privilegeMode = gba->cpu->cpsr.priv;
 	gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
 	if (state->biosPrefetch) {
-		gba->memory.biosPrefetch = state->biosPrefetch;
+		LOAD_32(gba->memory.biosPrefetch, 0, &state->biosPrefetch);
 	}
 	if (gba->cpu->cpsr.t) {
 		gba->cpu->executionMode = MODE_THUMB;
 		if (state->cpuPrefetch[0] && state->cpuPrefetch[1]) {
-			gba->cpu->prefetch[0] = state->cpuPrefetch[0] & 0xFFFF;
-			gba->cpu->prefetch[1] = state->cpuPrefetch[1] & 0xFFFF;
+			LOAD_32(gba->cpu->prefetch[0], 0, state->cpuPrefetch);
+			LOAD_32(gba->cpu->prefetch[1], 4, state->cpuPrefetch);
+			gba->cpu->prefetch[0] &= 0xFFFF;
+			gba->cpu->prefetch[1] &= 0xFFFF;
 		} else {
 			// Maintain backwards compat
 			LOAD_16(gba->cpu->prefetch[0], (gba->cpu->gprs[ARM_PC] - WORD_SIZE_THUMB) & gba->cpu->memory.activeMask, gba->cpu->memory.activeRegion);
@@ -128,8 +156,8 @@ bool GBADeserialize(struct GBA* gba, const struct GBASerializedState* state) {
 	} else {
 		gba->cpu->executionMode = MODE_ARM;
 		if (state->cpuPrefetch[0] && state->cpuPrefetch[1]) {
-			gba->cpu->prefetch[0] = state->cpuPrefetch[0];
-			gba->cpu->prefetch[1] = state->cpuPrefetch[1];
+			LOAD_32(gba->cpu->prefetch[0], 0, state->cpuPrefetch);
+			LOAD_32(gba->cpu->prefetch[1], 4, state->cpuPrefetch);
 		} else {
 			// Maintain backwards compat
 			LOAD_32(gba->cpu->prefetch[0], (gba->cpu->gprs[ARM_PC] - WORD_SIZE_ARM) & gba->cpu->memory.activeMask, gba->cpu->memory.activeRegion);
@@ -245,10 +273,39 @@ bool GBASaveState(struct GBAThread* threadContext, struct VDir* dir, int slot, b
 	bool success = GBASaveStateNamed(threadContext->gba, vf, screenshot);
 	vf->close(vf);
 	if (success) {
+#if SAVESTATE_DEBUG
+		vf = GBAGetState(threadContext->gba, dir, slot, false);
+		if (vf) {
+			struct GBA* backup = anonymousMemoryMap(sizeof(*backup));
+			memcpy(backup, threadContext->gba, sizeof(*backup));
+			memset(threadContext->gba->memory.io, 0, sizeof(threadContext->gba->memory.io));
+			memset(threadContext->gba->timers, 0, sizeof(threadContext->gba->timers));
+			GBALoadStateNamed(threadContext->gba, vf);
+			if (memcmp(backup, threadContext->gba, sizeof(*backup))) {
+				char suffix[16] = { '\0' };
+				struct VFile* vf2;
+				snprintf(suffix, sizeof(suffix), ".dump.0.%d", slot);
+				vf2 = VDirOptionalOpenFile(dir, threadContext->gba->activeFile, "savestate", suffix, write ? (O_CREAT | O_TRUNC | O_RDWR) : O_RDONLY);
+				if (vf2) {
+					vf2->write(vf2, backup, sizeof(*backup));
+					vf2->close(vf2);
+				}
+				snprintf(suffix, sizeof(suffix), ".dump.1.%d", slot);
+				vf2 = VDirOptionalOpenFile(dir, threadContext->gba->activeFile, "savestate", suffix, write ? (O_CREAT | O_TRUNC | O_RDWR) : O_RDONLY);
+				if (vf2) {
+					vf2->write(vf2, threadContext->gba, sizeof(*threadContext->gba));
+					vf2->close(vf2);
+				}
+			}
+			mappedMemoryFree(backup, sizeof(*backup));
+			vf->close(vf);
+		}
+#endif
 		GBALog(threadContext->gba, GBA_LOG_STATUS, "State %i saved", slot);
 	} else {
 		GBALog(threadContext->gba, GBA_LOG_STATUS, "State %i failed to save", slot);
 	}
+
 	return success;
 }
 
diff --git a/src/gba/serialize.h b/src/gba/serialize.h
index 32b322a8c..e33fb1792 100644
--- a/src/gba/serialize.h
+++ b/src/gba/serialize.h
@@ -184,6 +184,33 @@ extern const uint32_t GBA_SAVESTATE_MAGIC;
  * Total size: 0x61000 (397,312) bytes
  */
 
+DECL_BITFIELD(GBASerializedAudioFlags, uint32_t);
+DECL_BITS(GBASerializedAudioFlags, Ch1Volume, 0, 4);
+DECL_BIT(GBASerializedAudioFlags, Ch1Dead, 4);
+DECL_BIT(GBASerializedAudioFlags, Ch1Hi, 5);
+DECL_BITS(GBASerializedAudioFlags, Ch2Volume, 8, 4);
+DECL_BIT(GBASerializedAudioFlags, Ch2Dead, 12);
+DECL_BIT(GBASerializedAudioFlags, Ch2Hi, 13);
+DECL_BITS(GBASerializedAudioFlags, Ch4Volume, 16, 4);
+DECL_BIT(GBASerializedAudioFlags, Ch4Dead, 20);
+
+DECL_BITFIELD(GBASerializedHWFlags1, uint16_t);
+DECL_BIT(GBASerializedHWFlags1, ReadWrite, 0);
+DECL_BIT(GBASerializedHWFlags1, GyroEdge, 1);
+DECL_BIT(GBASerializedHWFlags1, LightEdge, 2);
+DECL_BITS(GBASerializedHWFlags1, LightCounter, 4, 12);
+
+DECL_BITFIELD(GBASerializedHWFlags2, uint8_t);
+DECL_BITS(GBASerializedHWFlags2, TiltState, 0, 2);
+DECL_BITS(GBASerializedHWFlags2, GbpInputsPosted, 2, 2);
+DECL_BITS(GBASerializedHWFlags2, GbpTxPosition, 4, 5);
+
+DECL_BITFIELD(GBASerializedHWFlags3, uint16_t);
+
+DECL_BITFIELD(GBASerializedSavedataFlags, uint8_t);
+DECL_BITS(GBASerializedSavedataFlags, FlashState, 0, 2);
+DECL_BIT(GBASerializedSavedataFlags, FlashBank, 4);
+
 struct GBASerializedState {
 	uint32_t versionMagic;
 	uint32_t biosChecksum;
@@ -236,18 +263,7 @@ struct GBASerializedState {
 		int32_t eventDiff;
 		int32_t nextSample;
 		uint32_t fifoSize;
-		unsigned ch1Volume : 4;
-		unsigned ch1Dead : 1;
-		unsigned ch1Hi : 1;
-		unsigned : 2;
-		unsigned ch2Volume : 4;
-		unsigned ch2Dead : 1;
-		unsigned ch2Hi : 1;
-		unsigned : 2;
-		unsigned ch4Volume : 4;
-		unsigned ch4Dead : 1;
-		unsigned : 3;
-		unsigned : 8;
+		GBASerializedAudioFlags flags;
 	} audio;
 
 	struct {
@@ -275,33 +291,23 @@ struct GBASerializedState {
 		uint16_t pinDirection;
 		struct GBARTC rtc;
 		uint8_t devices;
-		// Do not change these to uint16_t, this breaks bincompat with some older compilers
-		unsigned gyroSample : 16;
-		unsigned tiltSampleX : 16;
-		unsigned tiltSampleY : 16;
-		unsigned readWrite : 1;
-		unsigned gyroEdge : 1;
-		unsigned lightEdge : 1;
-		unsigned : 1;
-		unsigned lightCounter : 12;
-		unsigned lightSample : 8;
-		unsigned tiltState : 2;
-		unsigned gbpInputsPosted : 2;
-		unsigned gbpTxPosition : 5;
-		unsigned : 15;
-		uint32_t gbpNextEvent : 32;
+		uint16_t gyroSample;
+		uint16_t tiltSampleX;
+		uint16_t tiltSampleY;
+		GBASerializedHWFlags1 flags1;
+		uint8_t lightSample;
+		GBASerializedHWFlags2 flags2;
+		GBASerializedHWFlags3 flags3;
+		uint32_t gbpNextEvent;
 	} hw;
 
 	uint32_t reservedHardware[6];
 
 	struct {
-		unsigned type : 8;
-		unsigned command : 8;
-		unsigned flashState : 2;
-		unsigned : 2;
-		unsigned flashBank : 1;
-		unsigned : 3;
-		unsigned : 8;
+		uint8_t type;
+		uint8_t command;
+		GBASerializedSavedataFlags flags;
+		uint8_t reserved;
 		int32_t readBitsRemaining;
 		uint32_t readAddress;
 		uint32_t writeAddress;
diff --git a/src/gba/video.c b/src/gba/video.c
index 8855c018a..505ef4fa5 100644
--- a/src/gba/video.c
+++ b/src/gba/video.c
@@ -274,14 +274,13 @@ void GBAVideoSerialize(const struct GBAVideo* video, struct GBASerializedState*
 	memcpy(state->vram, video->renderer->vram, SIZE_VRAM);
 	memcpy(state->oam, video->oam.raw, SIZE_OAM);
 	memcpy(state->pram, video->palette, SIZE_PALETTE_RAM);
-	state->video.nextEvent = video->nextEvent;
-	state->video.eventDiff = video->eventDiff;
-	state->video.lastHblank = video->nextHblank - VIDEO_HBLANK_LENGTH;
-	state->video.nextHblank = video->nextHblank;
-	state->video.nextHblankIRQ = video->nextHblankIRQ;
-	state->video.nextVblankIRQ = video->nextVblankIRQ;
-	state->video.nextVcounterIRQ = video->nextVcounterIRQ;
-	state->video.frameCounter = video->frameCounter;
+	STORE_32(video->nextEvent, 0, &state->video.nextEvent);
+	STORE_32(video->eventDiff, 0, &state->video.eventDiff);
+	STORE_32(video->nextHblank, 0, &state->video.nextHblank);
+	STORE_32(video->nextHblankIRQ, 0, &state->video.nextHblankIRQ);
+	STORE_32(video->nextVblankIRQ, 0, &state->video.nextVblankIRQ);
+	STORE_32(video->nextVcounterIRQ, 0, &state->video.nextVcounterIRQ);
+	STORE_32(video->frameCounter, 0, &state->video.frameCounter);
 }
 
 void GBAVideoDeserialize(struct GBAVideo* video, const struct GBASerializedState* state) {
@@ -296,12 +295,12 @@ void GBAVideoDeserialize(struct GBAVideo* video, const struct GBASerializedState
 		LOAD_16(value, i, state->pram);
 		GBAStore16(video->p->cpu, BASE_PALETTE_RAM | i, value, 0);
 	}
-	video->nextEvent = state->video.nextEvent;
-	video->eventDiff = state->video.eventDiff;
-	video->nextHblank = state->video.nextHblank;
-	video->nextHblankIRQ = state->video.nextHblankIRQ;
-	video->nextVblankIRQ = state->video.nextVblankIRQ;
-	video->nextVcounterIRQ = state->video.nextVcounterIRQ;
-	video->frameCounter = state->video.frameCounter;
-	video->vcount = state->io[REG_VCOUNT >> 1];
+	LOAD_32(video->nextEvent, 0, &state->video.nextEvent);
+	LOAD_32(video->eventDiff, 0, &state->video.eventDiff);
+	LOAD_32(video->nextHblank, 0, &state->video.nextHblank);
+	LOAD_32(video->nextHblankIRQ, 0, &state->video.nextHblankIRQ);
+	LOAD_32(video->nextVblankIRQ, 0, &state->video.nextVblankIRQ);
+	LOAD_32(video->nextVcounterIRQ, 0, &state->video.nextVcounterIRQ);
+	LOAD_32(video->frameCounter, 0, &state->video.frameCounter);
+	LOAD_16(video->vcount, REG_VCOUNT, state->io);
 }
diff --git a/src/util/common.h b/src/util/common.h
index 9ffb1ed22..ef83d61f0 100644
--- a/src/util/common.h
+++ b/src/util/common.h
@@ -86,6 +86,7 @@ typedef intptr_t ssize_t;
 #define INS_BITS(SRC, START, END, BITS) (CLEAR_BITS(SRC, START, END) | (((BITS) << (START)) & MAKE_MASK(START, END)))
 #define CLEAR_BITS(SRC, START, END) ((SRC) & ~MAKE_MASK(START, END))
 #define FILL_BITS(SRC, START, END) ((SRC) | MAKE_MASK(START, END))
+#define TEST_FILL_BITS(SRC, START, END, TEST) ((TEST) ? (FILL_BITS(SRC, START, END)) : (CLEAR_BITS(SRC, START, END)))
 
 #ifdef _MSC_VER
 #define ATTRIBUTE_UNUSED
@@ -112,6 +113,9 @@ typedef intptr_t ssize_t;
 	} \
 	ATTRIBUTE_UNUSED static inline TYPE TYPE ## Set ## FIELD (TYPE src, TYPE bits) { \
 		return INS_BITS(src, (START), (START) + (SIZE), bits); \
+	} \
+	ATTRIBUTE_UNUSED static inline TYPE TYPE ## TestFill ## FIELD (TYPE src, bool test) { \
+		return TEST_FILL_BITS(src, (START), (START) + (SIZE), test); \
 	}
 
 #define DECL_BIT(TYPE, FIELD, BIT) DECL_BITS(TYPE, FIELD, BIT, 1)