I'm running KK 4.4.2 stock on Nexus 4, bootloader locked, unrooted. Never unlocked or rooted it.
It seems my issue started with the latest camera update; when I tried to take a shot with Lens Blur my phone shut down with a spark sound. I could reboot it fine though. I've had the same issue when using the camera in normal mode with the flash on, but I know it's a known bug on N4.
But since today I can't even switch my phone on unless it is plugged to power. I've tried rebooting in safe mode, I'm having the same issue. When it boots it would show the pretty animated logo, and right when the home screen should appear it'd turn off. Again, if plugged in no problem.
I did a factory-reset, no change. Switched back to factory version of camera, no change.
What do you think could be causing this issue? Is it a power or CPU overload of some kind?
Thanks a lot for your help!