diff --git a/first/scsi.i b/first/scsi.i
index 6b625fe..bff84b8 100644
--- a/first/scsi.i
+++ b/first/scsi.i
@@ -65,7 +65,7 @@ scsi_loop:
 	/* SCSISelect */
 
 	clr.w	-(%sp)
-	move.w	unit_id, -(%sp)
+	move.w	unit_id(%pc), -(%sp)
 	SCSIDispatch(_SCSISelect)
 
 	/* SCSICmd */