Help Serious crashing/rebooting problem - any ideas?

[squeakyg]

I've had the Nexus 7 2013 for about a month. It's unlocked/rooted with 4.4 and has been working fine.

This morning it was oddly powered off. A long press of the power button (about 15 seconds) boots it up again, but then it goes into a loop of booting to the lockscreen, freezing, and rebooting again. If it manages to boot up to a stable running state it may work for about 5 or 10 minutes, but then it will freeze and reboot (if in use), or go dead soon after turning off the screen.

Plugging it in to the charger or PC makes it stable and it works just fine, but as soon as it's removed from a power source the problems return. So while connected, I took the opportunity to flash stock + unroot, both with and without complete data wipes, and I flashed stock for various versions - 4.4.2, 4.4 and 4.3. None of these resolved the problem.

Any help?

I've relocked it so I can take it back to the shop, but it's been more than a month and I didn't take the extra insurance. Damn I hate this conversation I'll need to have in the shop tomorrow.

 

[Rukbat]

Turn it off. Plug in the charger. Wait AT LEAST 24 hours. Then see if it's stable.

 

[squeakyg]

Turn it off. Plug in the charger. Wait AT LEAST 24 hours. Then see if it's stable.

Alright, it's switched off and charging.

Are you suggesting a battery problem? The battery percentage has always been as expected, and it seemed to charge at an expected rate... although the usage graph looked glitchy, resetting after every reboot or unplugging. Even if things are stable after 24 hours, this is a fault that would concern me for the future.