diff --git a/libsrc/lynx/lynx-stdjoy.s b/libsrc/lynx/lynx-stdjoy.s
index ad7be4840..dc2d716ba 100644
--- a/libsrc/lynx/lynx-stdjoy.s
+++ b/libsrc/lynx/lynx-stdjoy.s
@@ -92,6 +92,7 @@ COUNT:
 READ:
        	ldx     #$00            ; Clear high byte
         lda     JOYSTICK        ; Read joystick
+        and     #$F3            ; Mask relevant keys
         rts