diff --git a/test/Makefile.am b/test/Makefile.am
index 19e85798..2dc846e4 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -691,7 +691,7 @@ if WORDS_BIGENDIAN
 else
 	diff $(srcdir)/test2.$@ test.$@1 >> test.log 2>&1
 endif
-	if [ $? ] ; then $(PRINTF) "\t\t\t\t%s\n" "FAILED"; else $(PRINTF) "\t\t\t\t%s\n" "OK"; fi
+	if [ $? ] ; then $(PRINTF) "\t\t\t\t%s\n" "FAILED"; xxd test.$@1 >> test.log 2>&1; else $(PRINTF) "\t\t\t\t%s\n" "OK"; fi
 
 rewrite_mtutrunc:
 	$(PRINTF) "%s" "[tcprewrite] MTU Truncate test: "