Index: buildroot/package/busybox/udhcpc.script
===================================================================
--- buildroot.orig/package/busybox/udhcpc.script	2017-10-14 14:55:16.374784277 -0400
+++ buildroot/package/busybox/udhcpc.script	2017-10-14 14:55:32.934958126 -0400
@@ -8,6 +8,7 @@
 [ -e $RESOLV_CONF ] || touch $RESOLV_CONF
 [ -n "$broadcast" ] && BROADCAST="broadcast $broadcast"
 [ -n "$subnet" ] && NETMASK="netmask $subnet"
+[ -n "$mtu" ] && MTU="mtu $mtu" || MTU="mtu 1500"
 
 case "$1" in
 	deconfig)
@@ -36,7 +37,7 @@
 		if [ -x /usr/sbin/avahi-autoipd ]; then
 			/usr/sbin/avahi-autoipd -k $interface
 		fi
-		/sbin/ifconfig $interface $ip $BROADCAST $NETMASK
+		/sbin/ifconfig $interface $ip $BROADCAST $NETMASK $MTU
 
 		if [ -n "$router" ] ; then
 			echo "deleting routers"