I have an interesting problem with an iPhone 5s I'm repairing for a client:
Background
The iPhone 5s was dropped in water and completely submerged for a seconds (I'm not sure if it was on or off when it fell in, but I can find out), but was quickly retrieved and still worked for a few minutes before the BSOD appeared and the iPhone restarted. My client immediately turned the iPhone off and texted me about trying to fix it, I agreed to try my best, and I received it the next day.
Additional Problems
I was also told that it was having a hard time recognizing touch input, detected buttons being pressed when they weren't, and inaccurately recognized headphones being plugged into the headphone jack when they weren't.
My Repair
I began to disassemble it as soon as I got home. I disconnected the digitizer assembly, took out the battery, logic board, and Lightning dock assembly. I noticed corrosion on the bottom of the board on the back , which I cleaned best I could with alcohol and a toothbrush, but is still stained and around a chip on the top of the board on the back. I cleaned the Lightning jack assembly the same way, but when I connected it to the board and tried to charge the iPhone, it didn't work. I cleaned the port on the board and it worked. After a few hours (disassembling, cleaning, testing, cleaning again, testing again, etc., then reassembling, the iPhone was at least working better than when it was brought to me and all of the above problems were fixed.
BSOD
However, upon unlocking the phone and testing it more thoroughly, the iPhone crashed with the BSOD and restarted. I timed it and it always happens between 2 and 3 minutes after being unlocked, however never appears on the lock screen.
Additional Info
- iPhone 5s is running iOS 9.2.1
- No iWork apps are installed (some said that iWork apps, like Pages, caused the BSOD when syncing to iCloud)
- I will try to relay any questions you have to my client
Any idea as to what is causing the BSOD and how I should fix it?
Update: I tested it with a different digitizer assembly (just the LCD and digitizer, no TouchID connected, no earpiece speaker, no front camera, nothing else) and to my amazement, it worked for almost 15 minutes before I decided to shut it off myself and put the old complete assembly back on. However, with everything (including TouchID) connected again, it went to the BSOD after a couple of minutes. I suspect TouchID.
Update 2: I believe that the above update was just a coincidence, as I just got the BSOD with the cracked screen.
Best Answer
After hours of testing many components, I think it's the battery at fault. Every battery has a processor inside of it which lets the iPhone know how much it's charged and handles other system-level battery stuff. The water must have majorly screwed up that processor and the battery itself, because I'll turn the iPhone on once and it'll read around 40% and it will work for 15 minutes straight, before I turn it off and then back on again. But then it'll either say something really low, like 12%, or really high, almost always in the 80%, but it will crash with the Blue Screen Of Death and restart itself. I put the battery from a family member's iPhone 5s in and it works, and no matter how many times I restart it, I get the actual charged percentage and no BSOD. I got this battery from iFixit, who I've had good luck with in the past.