Xiaomi Wifi Router 3G - 18.06.X / feedback and help

Hey. I want to update my openwrt to latest version with USB 3.0 patch, but i don't have my current image to flash in case of lastest one instability, how can I backup my current setup (i tried to backup kernel and ubi to img and then restore but this bricked my router after couple reboots)? Is there any archive site with older builds or something?