diff --git a/src/gb/audio.c b/src/gb/audio.c
index adaa44ff4..106e64a54 100644
--- a/src/gb/audio.c
+++ b/src/gb/audio.c
@@ -153,6 +153,10 @@ void GBAudioReset(struct GBAudio* audio) {
 	audio->playingCh2 = false;
 	audio->playingCh3 = false;
 	audio->playingCh4 = false;
+	if (audio->p && (audio->p->model == GB_MODEL_DMG || audio->p->model == GB_MODEL_CGB)) {
+		audio->playingCh1 = true;
+		*audio->nr52 |= 0x01;
+	}
 }
 
 void GBAudioResizeBuffer(struct GBAudio* audio, size_t samples) {
diff --git a/src/gb/gb.c b/src/gb/gb.c
index 3a24868ab..d4a5c3268 100644
--- a/src/gb/gb.c
+++ b/src/gb/gb.c
@@ -432,6 +432,8 @@ void GBReset(struct LR35902Core* cpu) {
 	cpu->b = 0;
 	cpu->d = 0;
 
+	gb->timer.internalDiv = 0;
+	int nextDiv = 0;
 	if (!gb->biosVf) {
 		switch (gb->model) {
 		case GB_MODEL_AUTODETECT: // Silence warnings
@@ -443,7 +445,8 @@ void GBReset(struct LR35902Core* cpu) {
 			cpu->e = 0xD8;
 			cpu->h = 1;
 			cpu->l = 0x4D;
-			gb->timer.internalDiv = 0x2AF3;
+			gb->timer.internalDiv = 0xABC;
+			nextDiv = 4;
 			break;
 		case GB_MODEL_SGB:
 			cpu->a = 1;
@@ -452,7 +455,8 @@ void GBReset(struct LR35902Core* cpu) {
 			cpu->e = 0x00;
 			cpu->h = 0xC0;
 			cpu->l = 0x60;
-			gb->timer.internalDiv = 0x2AF3;
+			gb->timer.internalDiv = 0xABC;
+			nextDiv = 4;
 			break;
 		case GB_MODEL_MGB:
 			cpu->a = 0xFF;
@@ -461,7 +465,8 @@ void GBReset(struct LR35902Core* cpu) {
 			cpu->e = 0xD8;
 			cpu->h = 1;
 			cpu->l = 0x4D;
-			gb->timer.internalDiv = 0x2AF3;
+			gb->timer.internalDiv = 0xABC;
+			nextDiv = 4;
 			break;
 		case GB_MODEL_SGB2:
 			cpu->a = 0xFF;
@@ -470,11 +475,20 @@ void GBReset(struct LR35902Core* cpu) {
 			cpu->e = 0x00;
 			cpu->h = 0xC0;
 			cpu->l = 0x60;
-			gb->timer.internalDiv = 0x2AF3;
+			gb->timer.internalDiv = 0xABC;
+			nextDiv = 4;
 			break;
 		case GB_MODEL_AGB:
+			cpu->a = 0x11;
 			cpu->b = 1;
-			// Fall through
+			cpu->f.packed = 0x00;
+			cpu->c = 0;
+			cpu->e = 0x08;
+			cpu->h = 0;
+			cpu->l = 0x7C;
+			gb->timer.internalDiv = 0x1EA;
+			nextDiv = 0xC;
+			break;
 		case GB_MODEL_CGB:
 			cpu->a = 0x11;
 			cpu->f.packed = 0x80;
@@ -482,7 +496,8 @@ void GBReset(struct LR35902Core* cpu) {
 			cpu->e = 0x08;
 			cpu->h = 0;
 			cpu->l = 0x7C;
-			gb->timer.internalDiv = 0x7A8;
+			gb->timer.internalDiv = 0x1EA;
+			nextDiv = 0xC;
 			break;
 		}
 
@@ -510,10 +525,10 @@ void GBReset(struct LR35902Core* cpu) {
 	GBMemoryReset(gb);
 	GBVideoReset(&gb->video);
 	GBTimerReset(&gb->timer);
-	mTimingSchedule(&gb->timing, &gb->timer.event, GB_DMG_DIV_PERIOD);
+	mTimingSchedule(&gb->timing, &gb->timer.event, nextDiv);
 
-	GBAudioReset(&gb->audio);
 	GBIOReset(gb);
+	GBAudioReset(&gb->audio);
 	GBSIOReset(&gb->sio);
 
 	GBSavedataUnmask(gb);
diff --git a/src/gb/io.c b/src/gb/io.c
index d8494a569..74adc850f 100644
--- a/src/gb/io.c
+++ b/src/gb/io.c
@@ -144,19 +144,19 @@ void GBIOReset(struct GB* gb) {
 	GBIOWrite(gb, REG_TAC, 0);
 	GBIOWrite(gb, REG_IF, 1);
 	GBIOWrite(gb, REG_NR52, 0xF1);
-	GBIOWrite(gb, REG_NR14, 0xBF);
+	GBIOWrite(gb, REG_NR14, 0x3F);
 	GBIOWrite(gb, REG_NR10, 0x80);
 	GBIOWrite(gb, REG_NR11, 0xBF);
 	GBIOWrite(gb, REG_NR12, 0xF3);
 	GBIOWrite(gb, REG_NR13, 0xF3);
-	GBIOWrite(gb, REG_NR24, 0xBF);
+	GBIOWrite(gb, REG_NR24, 0x3F);
 	GBIOWrite(gb, REG_NR21, 0x3F);
 	GBIOWrite(gb, REG_NR22, 0x00);
-	GBIOWrite(gb, REG_NR34, 0xBF);
+	GBIOWrite(gb, REG_NR34, 0x3F);
 	GBIOWrite(gb, REG_NR30, 0x7F);
 	GBIOWrite(gb, REG_NR31, 0xFF);
 	GBIOWrite(gb, REG_NR32, 0x9F);
-	GBIOWrite(gb, REG_NR44, 0xBF);
+	GBIOWrite(gb, REG_NR44, 0x3F);
 	GBIOWrite(gb, REG_NR41, 0xFF);
 	GBIOWrite(gb, REG_NR42, 0x00);
 	GBIOWrite(gb, REG_NR43, 0x00);
@@ -167,11 +167,14 @@ void GBIOReset(struct GB* gb) {
 	GBIOWrite(gb, REG_SCX, 0x00);
 	GBIOWrite(gb, REG_LYC, 0x00);
 	GBIOWrite(gb, REG_BGP, 0xFC);
-	GBIOWrite(gb, REG_OBP0, 0xFF);
-	GBIOWrite(gb, REG_OBP1, 0xFF);
+	if (gb->model < GB_MODEL_CGB) {
+		GBIOWrite(gb, REG_OBP0, 0xFF);
+		GBIOWrite(gb, REG_OBP1, 0xFF);
+	}
 	GBIOWrite(gb, REG_WY, 0x00);
 	GBIOWrite(gb, REG_WX, 0x00);
 	if (gb->model >= GB_MODEL_CGB) {
+		GBIOWrite(gb, REG_JOYP, 0xFF);
 		GBIOWrite(gb, REG_VBK, 0);
 		GBIOWrite(gb, REG_BCPS, 0);
 		GBIOWrite(gb, REG_OCPS, 0);
@@ -181,6 +184,8 @@ void GBIOReset(struct GB* gb) {
 		GBIOWrite(gb, REG_HDMA3, 0xFF);
 		GBIOWrite(gb, REG_HDMA4, 0xFF);
 		gb->memory.io[REG_HDMA5] = 0xFF;
+	} else if (gb->model == GB_MODEL_SGB) {
+		GBIOWrite(gb, REG_JOYP, 0xFF);
 	}
 	GBIOWrite(gb, REG_IE, 0x00);
 }
@@ -587,6 +592,9 @@ uint8_t GBIORead(struct GB* gb, unsigned address) {
 			case REG_SVBK:
 				// Handled transparently by the registers
 				goto success;
+			case REG_DMA:
+				mLOG(GB_IO, STUB, "Reading from unknown register FF%02X", address);
+				return 0;
 			default:
 				break;
 			}
diff --git a/src/gb/timer.c b/src/gb/timer.c
index 0e587410d..061fc8f2e 100644
--- a/src/gb/timer.c
+++ b/src/gb/timer.c
@@ -64,7 +64,6 @@ void GBTimerReset(struct GBTimer* timer) {
 
 	timer->nextDiv = GB_DMG_DIV_PERIOD; // TODO: GBC differences
 	timer->timaPeriod = 1024 >> 4;
-	timer->internalDiv = 0;
 }
 
 void GBTimerDivReset(struct GBTimer* timer) {