Chosen Solution

This one has me a little stumped.. I have an iPhone 7 that I got in a job lot. It’s cosmetically “perfect” and everything appears OK. It was missing the bottom screws which told me it had been opened. The battery wasn’t connected inside. I connected the charger (via amp meter), it draws 0 mA. Just on a whim, I tested with a known good charge port assembly, same result. I connected it to my desk PSU with a 7 squid, and it appeared to boot just fine (no screen connected). So I connected a screen and prompted it to boot again. Apple logo and perfectly reasonable readings from the PSU, but it just keeps looping. I have inspected the board under the microscope (though haven’t removed the shields yet) and there are no signs of anything wrong. Liquid indicators are crisp and white, no corrosion anywhere, nothing. I have no indications of a short, as the mA’s are well within reason, so my guess was a sensor that kept it looping, but I can’t get access to the kernel logs :(

I have found with the 7 series that boot-loops are commonly caused by: ·         The top flex cable. ·         The home button flex cable connecting to the logic board. ·         Audio IC. I have found if the audio IC is the problem it will eventually boot up. ·         Baseband CPU from a botched audio IC repair. Remove the sticker and see if it has had a repair attempt on the IC. If it has a prior repair on the audio IC it can also affect the Tristar IC as some of them are under filled. Also squids have a habit of causing boot-loops so I would suggest using a known good battery to rule out the squid.

So the tricky thing with iPhone 7 series is they are VERY boot loop prone. This could be any number of things, it can be difficult to narrow down. This could be an Audio IC issue, or a baseband issue, or a NAND issue. Usually a sensor issue will allow it to boot all the way and will reboot after some time. I am more likely to think it is something else. Is this something you need to get data off of? Or the person just wants it repaired. I might see if it will complete an update and make note of what error it gets if it fails.

Forcing your iPhone to restart can be the key to fixing the problem if it’s caused by some minor software glitches and errors. A forced restart on the iPhone 7 is done by simultaneously pressing and holding the Power button and the Volume Down button for at least 20 seconds or until the device power cycles. Greetings,Peter