diff -Nru ebtables-2.0.10.4/debian/changelog ebtables-2.0.10.4/debian/changelog
--- ebtables-2.0.10.4/debian/changelog	2018-05-21 17:20:15.000000000 +0000
+++ ebtables-2.0.10.4/debian/changelog	2018-06-28 16:42:04.000000000 +0000
@@ -1,3 +1,19 @@
+ebtables (2.0.10.4-3.5ubuntu2.18.04.3) bionic; urgency=medium
+
+  * Update versions to fix in prerm to Bionic's ebtables versions
+
+ -- Balint Reczey <rbalint@ubuntu.com>  Thu, 28 Jun 2018 18:42:04 +0200
+
+ebtables (2.0.10.4-3.5ubuntu2.18.04.2) bionic; urgency=medium
+
+  [ Dan Streetman ]
+  * Never return failure during ebtables.init stop(), it can cause
+    errors during package upgrade (LP: #1774120)
+  * Add version number check to prerm script, to only ignore
+    failed upgrade for older versions instead of all versions.
+
+ -- Balint Reczey <rbalint@ubuntu.com>  Thu, 28 Jun 2018 00:13:26 +0200
+
 ebtables (2.0.10.4-3.5ubuntu2.18.04.1) bionic; urgency=medium
 
   * Fix check of fcntl errno value, to allow lockfile contention to work.
diff -Nru ebtables-2.0.10.4/debian/ebtables.init ebtables-2.0.10.4/debian/ebtables.init
--- ebtables-2.0.10.4/debian/ebtables.init	2013-03-15 14:40:53.000000000 +0000
+++ ebtables-2.0.10.4/debian/ebtables.init	2018-06-28 16:42:04.000000000 +0000
@@ -49,7 +49,7 @@
 	/sbin/ebtables -t filter -L 2>&1 1>/dev/null | grep -q permission
 	if [ $? -eq 0 ]; then
 		log_failure_msg "Error: insufficient privileges to access the ebtables rulesets."
-		exit 1
+		return
 	fi
 	for table in filter nat broute; do
 		/sbin/ebtables -t $table -L &> /dev/null
@@ -140,6 +140,9 @@
   stop)
 	[ "$EBTABLES_SAVE_ON_STOP" = "yes" ] && save
 	clear
+	# Never return failure for stop; it's not helpful, and causes problems
+	# in some cases during pkg upgrade, e.g. LP: #1774120
+	RETVAL=0
 	;;
   restart|reload|force-reload)
 	[ "$EBTABLES_SAVE_ON_RESTART" = "yes" ] && save
diff -Nru ebtables-2.0.10.4/debian/ebtables.prerm ebtables-2.0.10.4/debian/ebtables.prerm
--- ebtables-2.0.10.4/debian/ebtables.prerm	1970-01-01 00:00:00.000000000 +0000
+++ ebtables-2.0.10.4/debian/ebtables.prerm	2018-06-28 16:42:04.000000000 +0000
@@ -0,0 +1,18 @@
+#!/bin/sh
+# prerm script for ebtables
+#
+# see: dh_installdeb(1)
+
+set -e
+
+if [ "$1" = "failed-upgrade" ]; then
+  # Ignore failed prerm on old versions; see LP: #1774120
+  dpkg --compare-versions "$2" lt "2.0.10.4-3.5ubuntu2.18.04.2" && exit 0
+fi
+
+# dh_installdeb will replace this with shell code automatically
+# generated by other debhelper scripts.
+
+#DEBHELPER#
+
+exit 0