maemo.org - Talk - N810 doesn't like to power up

I have a weird problem. I've searched here and google, and can't find any ideas, so here goes.

My N810 stays on for days just fine like it's supposed to. Problem is, if I turn it off, it doesn't want to turn back on. Pressing and holding the power button does nothing at all, and I AM sure I'm pressing hard enough.

I can try that any number of times and no go.

If I leave it unplugged from the charger, don't touch it for about 30 minutes, and then try again, it works fine.

I can't figure out what on earth is causing this. It seems like a firmware bug to me really.

But I've just upgraded to the latest firmware, and after restoring my backup, it shut off, and doesn't want to turn back on yet again. And the battery was full. Plugging in the AC adapter has no noticeable effect whatsoever when the device is in one of its "moods".

Ideas?