Hello,
I think its the antenna cable, since this is broken i have no signal on sim card 1 slot.
http://www.aliexpress.com/item/For-ASUS-Zenfone-2-ZE550ML-ZE551ML-Wifi-Antenna-Signal-Flex-Cable-free-shipping/32498968112.html?spm=2114.30010308.3.2.wRZvCC&ws_ab_test=searchweb201556_7,searchweb201602_4_10037_10017_10021_507_10022_10032_10020_10009_10008_10018_10019,searchweb201603_7&btsid=838c19ef-0df0-4d29-884b-c64cb7a56e70
I will buy this.