I turned my HTC One M7 phone off for the the device uptake thing, but instead of manually turning it back on, it turned on by itself. It says I'm connected to WiFi, but the blue WiFi calling icon at the top doesn't show. In the settings, it says it is trying to enable. After about 45 seconds, the phone's screen turns back, and 2 seconds later, the phone turns back on normally. This process is repeating itself over and over again. The phone is not rooted or has any custom software. I'm on android 4.3, and I did a soft boot, but that did not help either. Any help is appreciated. Thanks.
Are you using an OEM battery/charger? I was having same issue on a Samsung Galaxy S2 Android 4.0.4 when using non-OEM battery/external battery charger today. LED also blinks blue a second or 2 before powering on..
Performing a factory reset using hardware buttons
If you can’t turn HTC One on or access settings, you can still perform a factory reset by using the hardware buttons on HTC One.
Important: The Fast boot option in Settings > Power must not be selected.
Press and hold the VOLUME DOWN button, and then press and hold the POWER button.
Wait for the screen with the three Android images to appear, and then release the POWER and VOLUME DOWN buttons.
Press VOLUME DOWN to select FACTORY RESET, and then press the POWER button.