diff --git a/CHANGES b/CHANGES
index 0a46be2c2..21b34a1d2 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,6 @@
 0.7.0: (Future)
+Bugfixes:
+ - GB Audio: Fix zombie mode bit masking
 Misc:
  - GBA Timer: Use global cycles for timers
 
diff --git a/src/gb/audio.c b/src/gb/audio.c
index 3b384cdf8..3f4435731 100644
--- a/src/gb/audio.c
+++ b/src/gb/audio.c
@@ -702,6 +702,7 @@ bool _writeEnvelope(struct GBAudioEnvelope* envelope, uint8_t value) {
 	if (!envelope->stepTime) {
 		// TODO: Improve "zombie" mode
 		++envelope->currentVolume;
+		envelope->currentVolume &= 0xF;
 	}
 	_updateEnvelopeDead(envelope);
 	envelope->nextStep = envelope->stepTime;