How to operate 4G / Internet LEDs on ZBT WE1326

I was wondering about this for a while but never bothered to figure it out. Most of the LEDs seem to work out of the box but I could not get the 4G and Internet LEDs to do anything. They work with the original openwrt image which came with the device.

They are the 2nd and 4th LEDs from left when you look at the device from front. Does anybody know why they do not function? and how to get them to work?