diff --git a/coverage.sh b/coverage.sh
index eb8ebd2..294092c 100755
--- a/coverage.sh
+++ b/coverage.sh
@@ -117,7 +117,28 @@ tar -C /tmp/debian-$dist-debootstrap -xf "cache/debian-$dist-$variant.tar"
 # delete the directory
 tar -C /tmp/debian-$dist-debootstrap -cf dev1.tar ./dev
 tar -C /tmp/debian-$dist-mm -cf dev2.tar ./dev
-cmp dev1.tar dev2.tar
+ret=0
+cmp dev1.tar dev2.tar || ret=\$?
+if [ "\$ret" -ne 0 ]; then
+	if type diffoscope >/dev/null; then
+		diffoscope dev1.tar dev2.tar
+	else
+		echo "no diffoscope installed" >&2
+	fi
+	if type base64 >/dev/null; then
+		base64 dev1.tar
+		base64 dev2.tar
+	else
+		echo "no base64 installed" >&2
+	fi
+	if type xxd >/dev/null; then
+		xxd dev1.tar
+		xxd dev2.tar
+	else
+		echo "no xxd installed" >&2
+	fi
+	exit 1
+fi
 rm dev1.tar dev2.tar
 rm -r /tmp/debian-$dist-debootstrap/dev /tmp/debian-$dist-mm/dev