diff --git a/src/gba/io.c b/src/gba/io.c
index b70411094..ea2e1dc8d 100644
--- a/src/gba/io.c
+++ b/src/gba/io.c
@@ -342,248 +342,254 @@ void GBAIOInit(struct GBA* gba) {
 
 void GBAIOWrite(struct GBA* gba, uint32_t address, uint16_t value) {
 	if (address < REG_SOUND1CNT_LO && (address > REG_VCOUNT || address < REG_DISPSTAT)) {
-		value = gba->video.renderer->writeVideoRegister(gba->video.renderer, address, value);
-	} else {
-		switch (address) {
-		// Video
-		case REG_DISPSTAT:
-			value &= 0xFFF8;
-			GBAVideoWriteDISPSTAT(&gba->video, value);
-			return;
+		gba->memory.io[address >> 1] = gba->video.renderer->writeVideoRegister(gba->video.renderer, address, value);
+		return;
+	}
 
-		case REG_VCOUNT:
-			mLOG(GBA_IO, GAME_ERROR, "Write to read-only I/O register: %03X", address);
-			return;
+	if (address >= REG_SOUND1CNT_LO && address <= REG_SOUNDCNT_LO && !gba->audio.enable) {
+		// Ignore writes to most audio registers if the hardware is off.
+		return;
+	}
 
-		// Audio
-		case REG_SOUND1CNT_LO:
-			GBAAudioWriteSOUND1CNT_LO(&gba->audio, value);
-			value &= 0x007F;
-			break;
-		case REG_SOUND1CNT_HI:
-			GBAAudioWriteSOUND1CNT_HI(&gba->audio, value);
-			break;
-		case REG_SOUND1CNT_X:
-			GBAAudioWriteSOUND1CNT_X(&gba->audio, value);
-			value &= 0x47FF;
-			break;
-		case REG_SOUND2CNT_LO:
-			GBAAudioWriteSOUND2CNT_LO(&gba->audio, value);
-			break;
-		case REG_SOUND2CNT_HI:
-			GBAAudioWriteSOUND2CNT_HI(&gba->audio, value);
-			value &= 0x47FF;
-			break;
-		case REG_SOUND3CNT_LO:
-			GBAAudioWriteSOUND3CNT_LO(&gba->audio, value);
-			value &= 0x00E0;
-			break;
-		case REG_SOUND3CNT_HI:
-			GBAAudioWriteSOUND3CNT_HI(&gba->audio, value);
-			value &= 0xE03F;
-			break;
-		case REG_SOUND3CNT_X:
-			GBAAudioWriteSOUND3CNT_X(&gba->audio, value);
-			// TODO: The low bits need to not be readable, but still 8-bit writable
-			value &= 0x47FF;
-			break;
-		case REG_SOUND4CNT_LO:
-			GBAAudioWriteSOUND4CNT_LO(&gba->audio, value);
-			value &= 0xFF3F;
-			break;
-		case REG_SOUND4CNT_HI:
-			GBAAudioWriteSOUND4CNT_HI(&gba->audio, value);
-			value &= 0x40FF;
-			break;
-		case REG_SOUNDCNT_LO:
-			GBAAudioWriteSOUNDCNT_LO(&gba->audio, value);
-			value &= 0xFF77;
-			break;
-		case REG_SOUNDCNT_HI:
-			GBAAudioWriteSOUNDCNT_HI(&gba->audio, value);
-			value &= 0x770F;
-			break;
-		case REG_SOUNDCNT_X:
-			GBAAudioWriteSOUNDCNT_X(&gba->audio, value);
-			value &= 0x0080;
-			value |= gba->memory.io[REG_SOUNDCNT_X >> 1] & 0xF;
-			break;
-		case REG_SOUNDBIAS:
-			GBAAudioWriteSOUNDBIAS(&gba->audio, value);
-			break;
+	switch (address) {
+	// Video
+	case REG_DISPSTAT:
+		value &= 0xFFF8;
+		GBAVideoWriteDISPSTAT(&gba->video, value);
+		return;
 
-		case REG_WAVE_RAM0_LO:
-		case REG_WAVE_RAM1_LO:
-		case REG_WAVE_RAM2_LO:
-		case REG_WAVE_RAM3_LO:
-			GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
-			break;
+	case REG_VCOUNT:
+		mLOG(GBA_IO, GAME_ERROR, "Write to read-only I/O register: %03X", address);
+		return;
 
-		case REG_WAVE_RAM0_HI:
-		case REG_WAVE_RAM1_HI:
-		case REG_WAVE_RAM2_HI:
-		case REG_WAVE_RAM3_HI:
-			GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
-			break;
+	// Audio
+	case REG_SOUND1CNT_LO:
+		GBAAudioWriteSOUND1CNT_LO(&gba->audio, value);
+		value &= 0x007F;
+		break;
+	case REG_SOUND1CNT_HI:
+		GBAAudioWriteSOUND1CNT_HI(&gba->audio, value);
+		break;
+	case REG_SOUND1CNT_X:
+		GBAAudioWriteSOUND1CNT_X(&gba->audio, value);
+		value &= 0x47FF;
+		break;
+	case REG_SOUND2CNT_LO:
+		GBAAudioWriteSOUND2CNT_LO(&gba->audio, value);
+		break;
+	case REG_SOUND2CNT_HI:
+		GBAAudioWriteSOUND2CNT_HI(&gba->audio, value);
+		value &= 0x47FF;
+		break;
+	case REG_SOUND3CNT_LO:
+		GBAAudioWriteSOUND3CNT_LO(&gba->audio, value);
+		value &= 0x00E0;
+		break;
+	case REG_SOUND3CNT_HI:
+		GBAAudioWriteSOUND3CNT_HI(&gba->audio, value);
+		value &= 0xE03F;
+		break;
+	case REG_SOUND3CNT_X:
+		GBAAudioWriteSOUND3CNT_X(&gba->audio, value);
+		// TODO: The low bits need to not be readable, but still 8-bit writable
+		value &= 0x47FF;
+		break;
+	case REG_SOUND4CNT_LO:
+		GBAAudioWriteSOUND4CNT_LO(&gba->audio, value);
+		value &= 0xFF3F;
+		break;
+	case REG_SOUND4CNT_HI:
+		GBAAudioWriteSOUND4CNT_HI(&gba->audio, value);
+		value &= 0x40FF;
+		break;
+	case REG_SOUNDCNT_LO:
+		GBAAudioWriteSOUNDCNT_LO(&gba->audio, value);
+		value &= 0xFF77;
+		break;
+	case REG_SOUNDCNT_HI:
+		GBAAudioWriteSOUNDCNT_HI(&gba->audio, value);
+		value &= 0x770F;
+		break;
+	case REG_SOUNDCNT_X:
+		GBAAudioWriteSOUNDCNT_X(&gba->audio, value);
+		value &= 0x0080;
+		value |= gba->memory.io[REG_SOUNDCNT_X >> 1] & 0xF;
+		break;
+	case REG_SOUNDBIAS:
+		GBAAudioWriteSOUNDBIAS(&gba->audio, value);
+		break;
 
-		case REG_FIFO_A_LO:
-		case REG_FIFO_B_LO:
-			GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
-			return;
+	case REG_WAVE_RAM0_LO:
+	case REG_WAVE_RAM1_LO:
+	case REG_WAVE_RAM2_LO:
+	case REG_WAVE_RAM3_LO:
+		GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
+		break;
 
-		case REG_FIFO_A_HI:
-		case REG_FIFO_B_HI:
-			GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
-			return;
+	case REG_WAVE_RAM0_HI:
+	case REG_WAVE_RAM1_HI:
+	case REG_WAVE_RAM2_HI:
+	case REG_WAVE_RAM3_HI:
+		GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
+		break;
 
-		// DMA
-		case REG_DMA0SAD_LO:
-		case REG_DMA0DAD_LO:
-		case REG_DMA1SAD_LO:
-		case REG_DMA1DAD_LO:
-		case REG_DMA2SAD_LO:
-		case REG_DMA2DAD_LO:
-		case REG_DMA3SAD_LO:
-		case REG_DMA3DAD_LO:
-			GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
-			break;
+	case REG_FIFO_A_LO:
+	case REG_FIFO_B_LO:
+		GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
+		return;
 
-		case REG_DMA0SAD_HI:
-		case REG_DMA0DAD_HI:
-		case REG_DMA1SAD_HI:
-		case REG_DMA1DAD_HI:
-		case REG_DMA2SAD_HI:
-		case REG_DMA2DAD_HI:
-		case REG_DMA3SAD_HI:
-		case REG_DMA3DAD_HI:
-			GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
-			break;
+	case REG_FIFO_A_HI:
+	case REG_FIFO_B_HI:
+		GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
+		return;
 
-		case REG_DMA0CNT_LO:
-			GBADMAWriteCNT_LO(gba, 0, value & 0x3FFF);
-			break;
-		case REG_DMA0CNT_HI:
-			value = GBADMAWriteCNT_HI(gba, 0, value);
-			break;
-		case REG_DMA1CNT_LO:
-			GBADMAWriteCNT_LO(gba, 1, value & 0x3FFF);
-			break;
-		case REG_DMA1CNT_HI:
-			value = GBADMAWriteCNT_HI(gba, 1, value);
-			break;
-		case REG_DMA2CNT_LO:
-			GBADMAWriteCNT_LO(gba, 2, value & 0x3FFF);
-			break;
-		case REG_DMA2CNT_HI:
-			value = GBADMAWriteCNT_HI(gba, 2, value);
-			break;
-		case REG_DMA3CNT_LO:
-			GBADMAWriteCNT_LO(gba, 3, value);
-			break;
-		case REG_DMA3CNT_HI:
-			value = GBADMAWriteCNT_HI(gba, 3, value);
-			break;
+	// DMA
+	case REG_DMA0SAD_LO:
+	case REG_DMA0DAD_LO:
+	case REG_DMA1SAD_LO:
+	case REG_DMA1DAD_LO:
+	case REG_DMA2SAD_LO:
+	case REG_DMA2DAD_LO:
+	case REG_DMA3SAD_LO:
+	case REG_DMA3DAD_LO:
+		GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
+		break;
 
-		// Timers
-		case REG_TM0CNT_LO:
-			GBATimerWriteTMCNT_LO(gba, 0, value);
-			return;
-		case REG_TM1CNT_LO:
-			GBATimerWriteTMCNT_LO(gba, 1, value);
-			return;
-		case REG_TM2CNT_LO:
-			GBATimerWriteTMCNT_LO(gba, 2, value);
-			return;
-		case REG_TM3CNT_LO:
-			GBATimerWriteTMCNT_LO(gba, 3, value);
-			return;
+	case REG_DMA0SAD_HI:
+	case REG_DMA0DAD_HI:
+	case REG_DMA1SAD_HI:
+	case REG_DMA1DAD_HI:
+	case REG_DMA2SAD_HI:
+	case REG_DMA2DAD_HI:
+	case REG_DMA3SAD_HI:
+	case REG_DMA3DAD_HI:
+		GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
+		break;
 
-		case REG_TM0CNT_HI:
-			value &= 0x00C7;
-			GBATimerWriteTMCNT_HI(gba, 0, value);
-			break;
-		case REG_TM1CNT_HI:
-			value &= 0x00C7;
-			GBATimerWriteTMCNT_HI(gba, 1, value);
-			break;
-		case REG_TM2CNT_HI:
-			value &= 0x00C7;
-			GBATimerWriteTMCNT_HI(gba, 2, value);
-			break;
-		case REG_TM3CNT_HI:
-			value &= 0x00C7;
-			GBATimerWriteTMCNT_HI(gba, 3, value);
-			break;
+	case REG_DMA0CNT_LO:
+		GBADMAWriteCNT_LO(gba, 0, value & 0x3FFF);
+		break;
+	case REG_DMA0CNT_HI:
+		value = GBADMAWriteCNT_HI(gba, 0, value);
+		break;
+	case REG_DMA1CNT_LO:
+		GBADMAWriteCNT_LO(gba, 1, value & 0x3FFF);
+		break;
+	case REG_DMA1CNT_HI:
+		value = GBADMAWriteCNT_HI(gba, 1, value);
+		break;
+	case REG_DMA2CNT_LO:
+		GBADMAWriteCNT_LO(gba, 2, value & 0x3FFF);
+		break;
+	case REG_DMA2CNT_HI:
+		value = GBADMAWriteCNT_HI(gba, 2, value);
+		break;
+	case REG_DMA3CNT_LO:
+		GBADMAWriteCNT_LO(gba, 3, value);
+		break;
+	case REG_DMA3CNT_HI:
+		value = GBADMAWriteCNT_HI(gba, 3, value);
+		break;
 
-		// SIO
-		case REG_SIOCNT:
-			GBASIOWriteSIOCNT(&gba->sio, value);
-			break;
-		case REG_RCNT:
-			value &= 0xC1FF;
-			GBASIOWriteRCNT(&gba->sio, value);
-			break;
-		case REG_JOY_TRANS_LO:
-		case REG_JOY_TRANS_HI:
-			gba->memory.io[REG_JOYSTAT >> 1] |= JOYSTAT_TRANS_BIT;
-			// Fall through
-		case REG_SIODATA32_LO:
-		case REG_SIODATA32_HI:
-		case REG_SIOMLT_SEND:
-		case REG_JOYCNT:
-		case REG_JOYSTAT:
-		case REG_JOY_RECV_LO:
-		case REG_JOY_RECV_HI:
-			value = GBASIOWriteRegister(&gba->sio, address, value);
-			break;
+	// Timers
+	case REG_TM0CNT_LO:
+		GBATimerWriteTMCNT_LO(gba, 0, value);
+		return;
+	case REG_TM1CNT_LO:
+		GBATimerWriteTMCNT_LO(gba, 1, value);
+		return;
+	case REG_TM2CNT_LO:
+		GBATimerWriteTMCNT_LO(gba, 2, value);
+		return;
+	case REG_TM3CNT_LO:
+		GBATimerWriteTMCNT_LO(gba, 3, value);
+		return;
 
-		// Interrupts and misc
-		case REG_KEYCNT:
-			value &= 0xC3FF;
-			gba->memory.io[address >> 1] = value;
-			GBATestKeypadIRQ(gba);
+	case REG_TM0CNT_HI:
+		value &= 0x00C7;
+		GBATimerWriteTMCNT_HI(gba, 0, value);
+		break;
+	case REG_TM1CNT_HI:
+		value &= 0x00C7;
+		GBATimerWriteTMCNT_HI(gba, 1, value);
+		break;
+	case REG_TM2CNT_HI:
+		value &= 0x00C7;
+		GBATimerWriteTMCNT_HI(gba, 2, value);
+		break;
+	case REG_TM3CNT_HI:
+		value &= 0x00C7;
+		GBATimerWriteTMCNT_HI(gba, 3, value);
+		break;
+
+	// SIO
+	case REG_SIOCNT:
+		GBASIOWriteSIOCNT(&gba->sio, value);
+		break;
+	case REG_RCNT:
+		value &= 0xC1FF;
+		GBASIOWriteRCNT(&gba->sio, value);
+		break;
+	case REG_JOY_TRANS_LO:
+	case REG_JOY_TRANS_HI:
+		gba->memory.io[REG_JOYSTAT >> 1] |= JOYSTAT_TRANS_BIT;
+		// Fall through
+	case REG_SIODATA32_LO:
+	case REG_SIODATA32_HI:
+	case REG_SIOMLT_SEND:
+	case REG_JOYCNT:
+	case REG_JOYSTAT:
+	case REG_JOY_RECV_LO:
+	case REG_JOY_RECV_HI:
+		value = GBASIOWriteRegister(&gba->sio, address, value);
+		break;
+
+	// Interrupts and misc
+	case REG_KEYCNT:
+		value &= 0xC3FF;
+		gba->memory.io[address >> 1] = value;
+		GBATestKeypadIRQ(gba);
+		return;
+	case REG_WAITCNT:
+		value &= 0x5FFF;
+		GBAAdjustWaitstates(gba, value);
+		break;
+	case REG_IE:
+		gba->memory.io[REG_IE >> 1] = value;
+		GBATestIRQ(gba, 1);
+		return;
+	case REG_IF:
+		value = gba->memory.io[REG_IF >> 1] & ~value;
+		gba->memory.io[REG_IF >> 1] = value;
+		GBATestIRQ(gba, 1);
+		return;
+	case REG_IME:
+		gba->memory.io[REG_IME >> 1] = value & 1;
+		GBATestIRQ(gba, 1);
+		return;
+	case REG_MAX:
+		// Some bad interrupt libraries will write to this
+		break;
+	case REG_DEBUG_ENABLE:
+		gba->debug = value == 0xC0DE;
+		return;
+	case REG_DEBUG_FLAGS:
+		if (gba->debug) {
+			GBADebug(gba, value);
 			return;
-		case REG_WAITCNT:
-			value &= 0x5FFF;
-			GBAAdjustWaitstates(gba, value);
-			break;
-		case REG_IE:
-			gba->memory.io[REG_IE >> 1] = value;
-			GBATestIRQ(gba, 1);
-			return;
-		case REG_IF:
-			value = gba->memory.io[REG_IF >> 1] & ~value;
-			gba->memory.io[REG_IF >> 1] = value;
-			GBATestIRQ(gba, 1);
-			return;
-		case REG_IME:
-			gba->memory.io[REG_IME >> 1] = value & 1;
-			GBATestIRQ(gba, 1);
-			return;
-		case REG_MAX:
-			// Some bad interrupt libraries will write to this
-			break;
-		case REG_DEBUG_ENABLE:
-			gba->debug = value == 0xC0DE;
-			return;
-		case REG_DEBUG_FLAGS:
-			if (gba->debug) {
-				GBADebug(gba, value);
-				return;
-			}
-			// Fall through
-		default:
-			if (address >= REG_DEBUG_STRING && address - REG_DEBUG_STRING < sizeof(gba->debugString)) {
-				STORE_16LE(value, address - REG_DEBUG_STRING, gba->debugString);
-				return;
-			}
-			mLOG(GBA_IO, STUB, "Stub I/O register write: %03X", address);
-			if (address >= REG_MAX) {
-				mLOG(GBA_IO, GAME_ERROR, "Write to unused I/O register: %03X", address);
-				return;
-			}
-			break;
 		}
+		// Fall through
+	default:
+		if (address >= REG_DEBUG_STRING && address - REG_DEBUG_STRING < sizeof(gba->debugString)) {
+			STORE_16LE(value, address - REG_DEBUG_STRING, gba->debugString);
+			return;
+		}
+		mLOG(GBA_IO, STUB, "Stub I/O register write: %03X", address);
+		if (address >= REG_MAX) {
+			mLOG(GBA_IO, GAME_ERROR, "Write to unused I/O register: %03X", address);
+			return;
+		}
+		break;
 	}
 	gba->memory.io[address >> 1] = value;
 }