diff --git a/luci-app-openmptcprouter/root/etc/init.d/openmptcprouter b/luci-app-openmptcprouter/root/etc/init.d/openmptcprouter
index 189f2669b..e74aced38 100755
--- a/luci-app-openmptcprouter/root/etc/init.d/openmptcprouter
+++ b/luci-app-openmptcprouter/root/etc/init.d/openmptcprouter
@@ -177,7 +177,7 @@ start_service() {
 		else
 			rm -f /dev/sfe_ipv6
 		fi
-	else
+	elif [ -d "/sys/module/fast_classifier" ]; then
 		rmmod fast_classifier 2>&1 >/dev/null
 	fi
 
@@ -188,9 +188,9 @@ start_service() {
 			set firewall.zone_vpn.auto_helper='0'
 			commit firewall
 		EOF
-		rmmod nf_nat_sip 2>&1 >/dev/null
+		[ -n "$(lsmod | grep nf_nat_sip)" ] && rmmod nf_nat_sip 2>&1 >/dev/null
 		sleep 2
-		rmmod nf_conntrack_sip 2>&1 >/dev/null
+		[ -n "$(lsmod | grep nf_conntrack_sip)" ] && rmmod nf_conntrack_sip 2>&1 >/dev/null
 	else
 		uci -q batch <<-EOF >/dev/null
 			set firewall.zone_lan.auto_helper='1'
diff --git a/openmptcprouter/files/etc/uci-defaults/1980-omr-firewall b/openmptcprouter/files/etc/uci-defaults/1980-omr-firewall
index 07ea31f1f..5bab51455 100755
--- a/openmptcprouter/files/etc/uci-defaults/1980-omr-firewall
+++ b/openmptcprouter/files/etc/uci-defaults/1980-omr-firewall
@@ -258,8 +258,8 @@ if [ "$(uci -q get openmptcprouter.settings.sipalg)" = "0" ]; then
 		set firewall.zone_vpn.auto_helper='0'
 		commit firewall
 	EOF
-	rmmod nf_nat_sip 2>&1 >/dev/null
-	rmmod nf_conntrack_sip 2>&1 >/dev/null
+	[ -n "$(lsmod | grep nf_nat_sip)" ] && rmmod nf_nat_sip 2>&1 >/dev/null
+	[ -n "$(lsmod | grep nf_conntrack_sip)" ] && rmmod nf_conntrack_sip 2>&1 >/dev/null
 fi
 
 rm -f /tmp/luci-indexcache