Redmi 3s here. I installed LOS 16.0 and I put a SIM card in. No 3G or 4G. Tried different settings, APN's, different preferred connection types. When I call a number the phone switched to 3G and then internet started working until the next reboot. Sometimes 4G came on when I traveled between different BTS stations.
When I downgraded to 15.1 everything started working fine out of the box ie. 4G almost all the time.
Stock firmware is also working fine.
Anyone know how to get 3G/4G internet running in 16.1?