I bought a new iPhone SE about a month ago. Nice phone. Like it a lot. Works fine. However . . . I went outside yesterday afternoon. Phone was fully charged. Walked over to a local coffee shop, sat down, took out the phone, and it wouldn’t respond. Nothing. Dead. Fortunately, I’m close to an Apple Store. So, I walked over, checked in, and was seen by a rep at the fix-it counter. He plugged the phone in. Unplugged it, then pressed the buttons in sequence and the phone booted. I entered my code and all was good. I asked him what was going on and he said that the phone will sometimes “shut down” when going from a warm to a very cold environment to save “battery life.” This makes no sense to me but what do I know. Anyone ever heard of this or seen this behavior.
By the way, the key combination is Volume-up, then Volume-down, then Power button (hold for 20 seconds). You do that in sequence.
That’s the force-restart sequence. It will forcibly power-off and restart a phone, in the event that nothing else works.
It should only be used if in fact you have no other choice. it’s the functional equivalent to pulling the power cord on a desktop system. But in a case like yours, where the normal power-off/power-on sequence isn’t working, it is your only remaining option short of opening it up and disconnecting the battery.
As for why your phone crashed in this way, I don’t know. It clearly wasn’t a simple power-off, or the side-button would have restarted it without the force-restart sequence. Something in iOS or the hardware crashed, maybe due to the cold, but that’s about the most I can figure out from this description.
Thanks. Yeah. I mean, basically the phone was just sitting in the pocket of my jacket. So, I did the same today–same jacket, about the same temperature outside, walked to the same coffee shop, and no problem with the phone. I don’t think I could have accidentally powered it down while it was in my pocket (since you have to slide the confirmation) and, even if that had happened, it should have restarted with a simple press of the power button. If it happens again, I may ask Apple for a replacement.
Hmm. Interesting. Hadn’t thought about that. Hadn’t thought about apps crashing on iOS at all, but, then again, why not? I have an iCloud backup, yes. That’s how I set up this current phone. Don’t have that many apps on the phone, but it’s always possible that one of them misbehaved.