diff --git a/build_debian.sh b/build_debian.sh
index 185825cf34b..db9c09da0c5 100755
--- a/build_debian.sh
+++ b/build_debian.sh
@@ -166,6 +166,7 @@ sudo LANG=C chroot $FILESYSTEM_ROOT apt-get -y install      \
     file                    \
     ifupdown                \
     iproute2                \
+    iptables-persistent     \
     isc-dhcp-client         \
     sudo                    \
     vim                     \
diff --git a/slave.mk b/slave.mk
index ee89df4b4c8..b1bf64a35a6 100644
--- a/slave.mk
+++ b/slave.mk
@@ -51,7 +51,7 @@ distclean : .platform clean
 include $(RULES_PATH)/config
 include $(RULES_PATH)/functions
 include $(RULES_PATH)/*.mk
-ifneq ($(CONFIGURED_PLATFORM), undefined)
+ifneq ($(wildcard $(PLATFORM_PATH)),)
 include $(PLATFORM_PATH)/rules.mk
 endif