diff --git a/src/gpu_regs.c b/src/gpu_regs.c
index e5ff4fe8f7..3bcc4fd931 100644
--- a/src/gpu_regs.c
+++ b/src/gpu_regs.c
@@ -10,9 +10,9 @@
 
 static u8 sGpuRegBuffer[GPU_REG_BUF_SIZE];
 static u8 sGpuRegWaitingList[GPU_REG_BUF_SIZE];
-static bool8 sGpuRegBufferLocked;
-static bool8 sShouldSyncRegIE;
-static u16 sRegIE;
+static volatile bool8 sGpuRegBufferLocked;
+static volatile bool8 sShouldSyncRegIE;
+static vu16 sRegIE;
 
 static void CopyBufferedValueToGpuReg(u8 regOffset);
 static void SyncRegIE(void);