"...My phone got wet (not submerged) and I thought it was fine. Then later it only booted into this "connect to iTunes" mode. I packed it with silica gel (not rice) for a few days but it never got out of this mode. Even when I try to recover via iTunes I get a generic 4013 error. Anyway I will try the Recboot thing next and if that doesn't work probably will try sending it to you..."
Since I already knew the phone was stuck in recovery mode, and had been wet, I didn't attempt to turn it on, or plug it into iTunes and attempt a recovery. Doing so would have been a redundant waste of time. Recovery attempts were already tried, trying again isn't likely to change its status: DOA.
Opening the phone up, I immediately notice corrosion around the battery connection. After a closer look, I find it on the home button connector as well. The phone may not have been submerged, but it sure got wet and water has penetrated into the middle of the phone. The water indicating sensor near the battery was bright red. These should be white. Any shade of pink to red is evidence of moisture intrusion. Photo of the inside of the phone and initial impression below.
In this case, corrosion was not found under the shields. Just because it wasn't the case here is no excuse to leave the shields in place! If you can't safely remove them, get the phone to someone who can. The green dashed line indicates the solder joints that held the shield to the PCB. The red square outlines the visible corrosion on the PCB.
Pressing the new home button worked. After a few more attempts at getting the original home button to function, it was determined that it wasn't going to work. This is unfortunate because iOS devices with fingerprint scanners (like the 5S), where the fingerprint scanner is broken, the device will lose the scanning function. This is because the print scanner is paired to the phone's logic board. If this weren't the case, you could theoretically mount your phone's print scanner to someone else's phone and unlock it. Once the print scanner is broken, it's broken forever. However, so long as the connection to the logic board is intact, a replacement home button can function as just that, a home button.
The phone was packaged back up and sent back to its owner the day after it was received. Mike sent this message after receiving it,
"Trent as you know I ended up sending the phone to you and you did your magic. You saved my phone plus priceless vacation memories. Thank you!!!!"
Mike, thanks for being our inaugural mail-in repair just 6 weeks after launching the blog. Glad we were able to help you out and save those priceless memories.