Hey connect it to a pc
Download firmware from flyme website latest and stable one and put it in the internal memory
If u connect phone in recovery mode to pc.it shows a space and copy that file into it and u r done with it

Did it work yaah the upadate file is a zip one and once u paste it in the removal disk when in recovery mode connected to pc
Then just click on system upgrade and clear data and done
It checks ur firmware if it is not corrupted then it upgrades the phone and u r back on the phone