Why would my iPhone 6 be stuck in a dead battery boot loop? Okay, so I have a problem. My iPhone 6 died (it runs a non-jailbroken version of iOS, I used it as a test device for development applications, but I didn't do anything crazy with the firmware of the phone). I plugged the phone in and got an Apple logo, and then it died again. It's on a loop.

What it looks like is happening is, when the phone is charging, it's above 5% battery, so it turns on. However, for some odd reason, the phone doesn't turn on all the way when it boots up; instead, it just shuts off again.

Then the phone goes back to "charging from dead" again. It's in an infinite loop.

Why would this suddenly happen? It's an unjailbroken iPhone 6 running the latest iOS (non-beta, iOS 8.4). How would I fix this?
In such cases I, myself, do a boot into DFU mode which actually uses way less energy mainly because the display stays off. 
Then I wait for about a half an hour and then I reboot the iDevice in order to have it properly booted. 

P.S. Follow this procedure in order to enter an iDevice into DFU mode:


Make sure your iDevice is plugged into a power source via it's USB cable; 
Hold down both Home and Power buttons on the iDevice for about 10 seconds until the screen goes off; 
Keep holding the Home button and release the Power button; 
Open  iTunes to check if the iDevice is connected. A message saying that an iDevice in a Recovery mode is connected should show up.