This guide is for MTK (e.g Tecno, Gionee, Infinix, Opsson, Micromax etc) Android phones
We've seen OTA bricks involving both rooted and non-rooted devices so rooting can't be said to be the ultimate cause, only a possible contributing factor.
It often starts with you getting a prompt saying "an update is available" or you going to Settings > About > System update .
If after the update, your phone only boots straight to recovery mode as in the picture above then fixing it is very easy.
All you need to do is download the firmware / stock ROM for your exact phone model @ https://forum.hovatek.com/forum-89.html then flash boot.img and system.img (Android) using SP flash tool @ https://forum.hovatek.com/thread-159.html .