diff --git a/src/gba/video.c b/src/gba/video.c
index 8717763c9..d4f9d256e 100644
--- a/src/gba/video.c
+++ b/src/gba/video.c
@@ -226,7 +226,38 @@ static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer) {
 
 static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value) {
 	UNUSED(renderer);
-	UNUSED(address);
+	switch (address) {
+	case REG_BG0CNT:
+	case REG_BG1CNT:
+		value &= 0xDFFF;
+		break;
+	case REG_BG2CNT:
+	case REG_BG3CNT:
+		value &= 0xFFFF;
+		break;
+	case REG_BG0HOFS:
+	case REG_BG0VOFS:
+	case REG_BG1HOFS:
+	case REG_BG1VOFS:
+	case REG_BG2HOFS:
+	case REG_BG2VOFS:
+	case REG_BG3HOFS:
+	case REG_BG3VOFS:
+		value &= 0x01FF;
+		break;
+	case REG_BLDCNT:
+		value &= 0x3FFF;
+		break;
+	case REG_BLDALPHA:
+		value &= 0x1F1F;
+		break;
+	case REG_WININ:
+	case REG_WINOUT:
+		value &= 0x3F3F;
+		break;
+	default:
+		break;
+	}
 	return value;
 }