my problem is that when i turn on my device he's stuck on the white M symbol... i was told that if i will flash maybe it will fix my problem but it doesn't worked apparently..
do you any solution for me ?
Ironically enough when you flash an SBF it is pretty common to bootloop after it. Try booting into Android (stock) recovery and doing a factory reset and cache wipe. I am trying to look up how to get into recovery on your phone right now in case you are not sure.