Connect the KEYone to a computer via USB and run the autoloader. This will wipe all data but should restore the OS. Failing Battery
Use the Volume buttons to scroll down to . Press the Power button to select it. Confirm the action by selecting Yes or Factory data reset . blackberry keyone stuck in bootloader menu
A physically jammed Volume Down button will force the phone into bootloader mode every time it powers on. Connect the KEYone to a computer via USB