OpenWrt for Xiaomi Mi Router 4C

Hi guys! I have been using my MI router 4C with openwrt for a while (Thanks to you @MacTavishAO). I have tried implementing mesh using 2 MI4C routers. But couldn't get it to work. Is there any limitation in hardware or software in the router that prevents me from implementing 802.11s or its just me making some mistake? Thanks!