WRT1900AC and WAN status, amber LED

Hi, everyone!

On stock WRT1900AC firmware WAN LED can become amber on no/lost uplink and white when uplink is good.

But on LEDE firmware I can't use the same option, because there is no "link OFF" option for netdev trigger.

Is there any way to get this option or I need a cron script for manuall amber LED processing?

Thanks in advance!

UPD. After some research I've found out that for some reason LuCi doesn't see change of status on WAN port - I deatach the cable from the port, and LuCi still shows that eth1 is still connected. It is odd, because my TP-LINK 4300 shows exact status of WAN port - after I unplug the cable, IPv4 WAN Status soon becomes "Not connected". So actual problem is not LED management - the problem is that LEDE firmware doesn't see WAN port status change.