Post #1505601

In last week's episode of exasperating but fascinating nerdy discovery, my son dropped his iPhone SE 2nd generation. Thereafter, it hard crashed and rebooted very frequently. We ended up getting him a second hand replacement. But I still had the challenge of getting the data off the old phone, since he doesn't have enough iCloud storage to have a recent cloud backup. Neither a transfer or computer backup was an option. Neither of those can be resumed and they never finished before the phone crashed and rebooted. But then I started to notice that the phone was crashing every 3 minutes. That looked suspiciously like a watchdog timer, so I started digging. It turns out that the phone has a damaged thermal sensor. To prevent itself from overheating (which can be very bad, especially in a device with a battery), the iPhone has a monitoring daemon (thermalmonitord). If it doesn't get a response from one of the thermal sensors within 3 minutes, that causes a kernel panic, force restarting the device to protect it. Thankfully, there is an exploit which allows one to disable thermalmonitord. As noted above, this is pretty dangerous, so I wrapped the phone in an ice pack to keep it from potentially overheating. That allowed me to complete a backup and thus restore it to his new phone. I also found instructions to fix the hardware failure. Unfortunately, I'm incapable of executing them myself, but I should hopefully be able to find a repair person who is. Hopefully, my diagnosis will make this a lot faster to repair and thus cost me less.