If the Light Phone II crashes for whatever reason and you are unable to power on the device with a normal long-press of the POWER button on the top of the phone, please try a hard reboot.
To hard reboot, first plug in the phone to a charger using the provided micro USB cord and then hold the POWER button and the VOLUME DOWN (lower small button on the right side of the phone) at the same time for 20-30 seconds. You will feel a vibration feedback from the phone and then it will begin to reboot. The phone should boot normally hereafter.