diff --git a/c64/kernal/iec_wait_for_clock_assert.s b/c64/kernal/iec_wait_for_clock_assert.s
index 04727971..aa661af9 100644
--- a/c64/kernal/iec_wait_for_clock_assert.s
+++ b/c64/kernal/iec_wait_for_clock_assert.s
@@ -1,5 +1,5 @@
 iec_wait_for_clock_assert:
 	LDA $DD00
-	and #$80
+	and #$40
 	bne iec_wait_for_clock_assert
 	rts