How to backup and restore the firmware on an MTK6580
How to dump a firmware file WITHOUT user data, how to restore a firmware file from a ROM file, how to create a firmware file for Flash Tool from a ROM file.
Instructions on 4PDA https://goo.gl/fzyoTi
Oukitel U7 Pro http://ali.pub/1beavb
AliExpress in Russian http://ali.pub/tjfkm