diff --git a/firmware/src/main.cpp b/firmware/src/main.cpp
index b162d84..3f655ba 100755
--- a/firmware/src/main.cpp
+++ b/firmware/src/main.cpp
@@ -205,7 +205,7 @@ bool set_key(uint16_t keycode, uint8_t kstate)
     }
 
     // Mouse buttons
-    if (keycode >= KEY_M1 && keycode <= KEY_MF)
+    if (keycode >= KEY_M1 && keycode <= KEY_M3)
     {
         if (kstate == RELEASED)
         {