diff --git a/c64/kernal/keyboard/scnkey.s b/c64/kernal/keyboard/scnkey.s
index e7c4d736..821abfa1 100644
--- a/c64/kernal/keyboard/scnkey.s
+++ b/c64/kernal/keyboard/scnkey.s
@@ -58,11 +58,11 @@ SCNKEY:
 
 	// First check if this is really a C128 - to avoid false positive
 	lda #$00
-#if !CONFIG_KEYBOARD_C128
-	tax
-#endif
 	sta VIC_XSCAN
 	lda #$FF
+#if !CONFIG_KEYBOARD_C128
+	tax                                // preserve the $FF, will be needed later
+#endif
 	cmp VIC_XSCAN
 	beq !+                             // branch if C64, C128 will keep some bits cleared