diff --git a/src/rp2_common/hardware_hazard3/include/hardware/hazard3.h b/src/rp2_common/hardware_hazard3/include/hardware/hazard3.h
index f1480b8cc..8484d12db 100644
--- a/src/rp2_common/hardware_hazard3/include/hardware/hazard3.h
+++ b/src/rp2_common/hardware_hazard3/include/hardware/hazard3.h
@@ -4,8 +4,8 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef _HARDWARE_HAZARD3_
-#define _HARDWARE_HAZARD3_
+#ifndef _HARDWARE_HAZARD3_H
+#define _HARDWARE_HAZARD3_H
 
 #include "pico.h"
 #include "hardware/riscv.h"