Cannot FF M55

[msh]

I have some problems with my M55, biggest of them - in charging process, when battery is full, it switches off Two years ago, when this was my main phone, i tried upload fullflash from other M55, result - ir doesn't even boot, so i bring it to workshop, they flashed it, by using testpoint, but error is still there Two weeks ago i tried upload backup firmware from this page, result - it doesn't worked, but, at last, i was able tu upload backup. What can i do?