diff --git a/CHANGES b/CHANGES
index c73b2528b..a0b87e214 100644
--- a/CHANGES
+++ b/CHANGES
@@ -24,6 +24,7 @@ Other fixes:
  - Debugger: Fix writing to specific segment in command-line debugger
  - GB: Fix uninitialized save data when loading undersized temporary saves
  - GBA Audio: Fix crash if audio FIFOs and timers get out of sync
+ - GBA Audio: Fix crash in audio subsampling if timing lockstep breaks
  - GBA Memory: Let raw access read high MMIO addresses
  - Qt: Fix savestate preview sizes with different scales (fixes mgba.io/i/2560)
  - Qt: Fix potential crash when configuring shortcuts
diff --git a/include/mgba/internal/gba/audio.h b/include/mgba/internal/gba/audio.h
index 5b5db3a62..fba5090bf 100644
--- a/include/mgba/internal/gba/audio.h
+++ b/include/mgba/internal/gba/audio.h
@@ -80,7 +80,7 @@ struct GBAAudio {
 	int32_t sampleInterval;
 
 	int32_t lastSample;
-	int sampleIndex;
+	unsigned sampleIndex;
 	struct mStereoSample currentSamples[GBA_MAX_SAMPLES];
 
 	bool forceDisableChA;
diff --git a/src/gba/audio.c b/src/gba/audio.c
index 25e400b19..a6ebafbae 100644
--- a/src/gba/audio.c
+++ b/src/gba/audio.c
@@ -232,6 +232,9 @@ void GBAAudioWriteSOUNDBIAS(struct GBAAudio* audio, uint16_t value) {
 	if (oldSampleInterval != audio->sampleInterval) {
 		timestamp -= audio->lastSample;
 		audio->sampleIndex = timestamp >> (9 - GBARegisterSOUNDBIASGetResolution(value));
+		if (audio->sampleIndex >= GBA_MAX_SAMPLES) {
+			audio->sampleIndex = 0;
+		}
 		if (audio->p->stream && audio->p->stream->audioRateChanged) {
 			audio->p->stream->audioRateChanged(audio->p->stream, GBA_ARM7TDMI_FREQUENCY / audio->sampleInterval);
 		}