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I have an iPhone 7 plus that I recently repaired that the ear speaker works randomly and the front camera is very slow at coming up and/or sometimes doesn’t work in apps such as snapchat. This iPhone has been fixed previously and has been working fine. Now I’ve replaced the front camera and speaker with a known working original with the same results. I also uncovered another issue. The phone will get stuck on the Apple logo after rebooting and will only boot normally after I do a hard reset. I tried different batteries and a different front camera flex with the same result. At this point Im scared to update to 11.3.1 or even restore it, because I’m afraid it wont boot properly and brick the phone Any words of wisdom before the customer makes an insurance claim? Is this maybe a software issue and not a hardware issue?
The iPhone 7 series of devices suffers from issues with the Baseband IC, Audio IC and weak traces on the pcb which crack and break. It is a similar design flaw to the iPhone 6 Plus, known as Touch Disease. On the iPhone 7 series, the weak traces are underneath the Audio IC. In many cases an internal short within the Baseband IC causes the boot looping, which unfortunately, is not repairable because the Baseband is code locked to the logic board. It can also be caused by a broken trace underneath the Audio IC. Replacing the Audio IC and strengthening the weak trace with a micro-jumper can repair this. If you are curious about the technical nature of these failures, you can listen to this video from Jessa and this one from Jason at STS, they go into a lot of detail regarding this issue. It could be BB or Audio but the info in the video should help you figure out which one.
