diff --git a/CHANGES b/CHANGES
index 84e82e87e..2a9f8a63b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -21,6 +21,7 @@ Bugfixes:
  - GBA Hardware: Improve Game Boy Player rumble behavior
  - GB: Initialize audio properly
  - GB MBC: Fix RTC access when no save file is loaded
+ - GB: Properly clear KEY1 bit 0 when switching speeds
 Misc:
  - All: Only update version info if needed
  - FFmpeg: Encoding cleanup
diff --git a/src/gb/gb.c b/src/gb/gb.c
index 1322f504b..d467b6da2 100644
--- a/src/gb/gb.c
+++ b/src/gb/gb.c
@@ -572,7 +572,7 @@ void GBStop(struct LR35902Core* cpu) {
 	}
 	if (gb->memory.io[REG_KEY1] & 1) {
 		gb->doubleSpeed ^= 1;
-		gb->memory.io[REG_KEY1] &= 1;
+		gb->memory.io[REG_KEY1] = 0;
 		gb->memory.io[REG_KEY1] |= gb->doubleSpeed << 7;
 	} else if (cpu->bus) {
 		if (cpu->components && cpu->components[CPU_COMPONENT_DEBUGGER]) {