Press and hold the Power button for 10–20 seconds
Use the Volume keys to select Reboot system now, then press Power
Disconnect the USB cable from the device
Remove the battery if the device has a removable battery, then reinsert it and power on
If using a computer, run `fastboot reboot`
If the device is frozen, force restart it with the Power button combination for your model
If it keeps returning to Fastboot mode, boot into recovery and reboot from there
If none of the above works, let the battery drain completely, then charge and restart