diff --git a/sys/dev/disk/mpt/mpt_pci.c b/sys/dev/disk/mpt/mpt_pci.c
--- a/sys/dev/disk/mpt/mpt_pci.c
+++ b/sys/dev/disk/mpt/mpt_pci.c
@@ -606,7 +606,7 @@
 	/*
 	 * but return zero to preserve unit numbering
 	 */
-	return (0);
+	return (ENXIO);
 }
 
 /*