To fix BitLocker on the Asus ROG Ally, your friend can follow these steps:
- Press and hold the power button on the device until it turns off completely.
- Press the power button again to turn on the device.
- When the BitLocker recovery screen appears, press the volume up button to switch to keyboard mode.
- Press inside the box and a keypad will appear.
- Enter the recovery key using the keypad.
- Once the recovery key is entered, the device should unlock and allow access to the operating system.
If your friend does not have the recovery key, he can try to retrieve it by following the steps in Finding your BitLocker recovery key in Windows - Microsoft Support.