After Rebooting i get white screen
and when i restore the backup it works for me
but i want to upgrade the android version
how can i do this ?
I faced the same problem,
This is because of firmware carriers ,
You will have to flash stock firmware of another country ( not yours ) for example USA or England , Root your device , Flash TWRP then do a System , Data , cache & dalvik cache Wipe then flash Speed Mod & GApps & It will work for you