If your HTC One suddenly shut off automatically without cause and subsequently no longer can turn on, then you can try this trick on your phone again to make it work. This requires that the HTC One reactivate the following key combination:
Pressed and hold both buttons at the same time following the HTC One:
- Power On / Off button
- Volume "down" button
Hold this key combination for about 10 seconds and the smartphone is a sg Perform "hard reboot". This roughly corresponds to removing the battery, as it was earlier in smartphones the case. This hard-reboot should have your HTC one brought back to life. Important! Depends on your HTC One now to a charger, since with very high probability much battery power is consumed by the error.