HTC One X+ reboots over and over - but only when I'm not using it?

[willcesium]

I have an HTC One X+, just over a year old. Yesterday, it started rebooting itself over and over, every 30 seconds to 2 minutes. Weirdly, it DOESN'T reboot when I'm actively using an app on it - just when it's sitting idle. So, it's not a boot loop per se - it boots fine, and I can use it - but as soon as I put it down, or put it in my pocket, it goes back into the re-re-start cycle. Which, I think, makes it not quite the same

At first I figured it might be a battery thing, so I let it drain all the way then charge. As soon as I plug it in to charge, it turns itself ON, and keeps rebooting. How it can do that even with fast boot turned off, I have no idea.

I tried booting in safe mode, and it still keeps restarting. Tried factory reset (3-4 times), and that doesn't help either. I've tried it from the boot loader, and from the settings menu, both wiped all my apps, but neither solved the problem.

When I try to boot to recovery, I get this horrible red triangle with exclamation mark. I tried wiping the cache from there, and when I do, it goes to a green circle screen with a progress bar. But the progress bar doesn't seem to start filling before it resets again.

I don't have root, and haven't really messed with it besides installing apps from play store - which I haven't done in more than a week. So I can't imagine anything I did caused the problem. But I also can't imagine that it's a hardware problem (e.g. fault in the power button) because presumably then it would happen regardless of what's open or running.

Taking it to a shop for repairs is not really an option - I live in South Africa, and there's no one who repairs HTC anything within 1000 miles or so. What else can I do?

 

[the tall guy]

It could be a loose battery, and when you are using the phone in an app you might have pressure on the back so it doesn't boot on and off?? have you tried holding it tight at the back and seeing if it turns off?

 

[willcesium]

Interesting idea - thanks for the suggestion!
It's not a removable battery so it's kind of hard to know where to press. But I tried squeezing it pretty tight and pressing my thumb on the screen from reboot. And it still reboots randomly on its own.
So I'm guessing it's not a loose battery then.

Anything else to try?

 

[willcesium]

Update: I've discovered that when I set it to never turn the screen off, it stays on, and doesn't keep rebooting. But if I then turn off the screen, it does reboot after a few seconds.
That can't be a loose battery thing, then - the battery would be just as loose whether the screen is on or off. It only seems to reboot when the screen goes off.
...and yet multiple factory resets haven't fixed anything.

 

[tomzdeenigma]

Is your device rooted? If not try installing ARHD.

 

[willcesium]

Not rooted, so I'd like to give that a try. But what is ARHD? The number one hit on google is Android Revolution HD. Is that what you meant?

I've been thinking if I could re-flash the stock ROM, that might fix things. Since it only reboots when system-managed screen changes happen, it can't be hardware - so I'm guessing something bit in the OS got corrupted somehow. Would flashing a different ROM fix that?

 

[willcesium]

Discovery of the day: Android Revolution HD is not available for the AT&T version of HOX+

:/