diff --git a/sys/dev/ow/ow.c b/sys/dev/ow/ow.c
index f5b5c6b980a..09236f0cd84 100644
--- a/sys/dev/ow/ow.c
+++ b/sys/dev/ow/ow.c
@@ -401,6 +401,8 @@ again:
 				if (++retries > 5)
 					return (EIO);
 				goto again;
+			default: /* NOTREACHED */
+				__unreachable();
 			}
 			if (dir) {
 				OWLL_WRITE_ONE(lldev, &timing_regular);