Chosen Solution
This phone had touch disease. I flowed a little Amtech flux under the touch ICs and gave it a little heat. I didn’t go crazy with heat. Just enough to get the surrounding components molten. Did not touch anything and board was taped down with kapton. Upon connecting the battery and USB I get a black screen. CPU gets warm. PC recognizes the phone in recovery mode. I tried restoring and it says “software for this phone is not available” and it is also not detecting the serial number. I have tried a few different recovery programs to kick it out of recovery mode, but it is not detected in these programs. Only in itunes. USB amp meter says it immediately starts pulling 0.5A when I plug it in, which is the max of the USB port. Did I create a short somewhere?
Hi Matt. Sorry, I accidentally deleted my original answer (I clicked delete instead of edit). Seeing as how you are well equipped and experienced, the only thing I can see is that too much heat was applied, despite the careful steps you took. At this point you need to check all of the surrounding components to see if anything came loose or if there are any solder balls laying around. FWIW, I personally don’t recommend reflowing IC’s on iDevice logic boards. The component density is too high and the actual pcb is too thin. The heat flows very quickly and the chips that are secured with underfill are particularly susceptible to solder ball merges or explosive expulsions. Once you start applying heat, it has to be for a specific purpose. In the case of Touch Disease, you should only apply heat when you intend to replace them. Don’t forget that a portion of the CPU is directly opposite the Touch IC’s.
Why are you reflowing? That is only a temporary fix and it’s going to just go bad again in a month or so. It can also cause more problems like Minho said. A better solution is to reball the chip or replace it. The reason behind this is because the solder balls are lead free and when rebslling it you can remove the old solder and use leaded solder. If it’s a temp fix for data recovery purposes then I understand.
