diff --git a/bin/pax/buf_subs.c b/bin/pax/buf_subs.c
index 4922fc80ffa0..40affa5c0f5e 100644
--- a/bin/pax/buf_subs.c
+++ b/bin/pax/buf_subs.c
@@ -852,10 +852,13 @@ buf_fill(void)
 
 		/*
 		 * errors require resync, EOF goes to next archive
+		 * but in case we have not determined yet the format,
+		 * this means that we have a very short file, so we
+		 * are done again.
 		 */
 		if (cnt < 0)
 			break;
-		if (ar_next() < 0) {
+		if (frmt == NULL || ar_next() < 0) {
 			fini = 1;
 			return(0);
 		}