So I'm struggling to isolate the issue. Replaced the back case and evidently I blew my proximity sensor because the sensor and the earpiece wouldn't work. I purchased a new one and replaced it, which resolved the proximity sensor issue...but the earpiece still isn't working. Here's my results of my attempts to troubleshoot: 1. Swapped screen into a known working phone. Results: Doesn't work in the working phone either. Proximity sensor still works. (this led me to believe the issue was with the earpiece itself...but I can't wrap my head around how I could've messed up the earpiece as well). 2. Put a screen with a known working earpiece into the this phone. Results: Known-working earpiece doesn't work in this phone either, which led me to believe there's something wrong with the logic board perhaps. Misc notes: - I've confirmed that I can utilize the speakerphone and a pair of iphone headphones without issue. - All other aspects of the phone work. - When I call someone with the "bad" phone, they can hear me just fine. I'm mechanically and technically inclined and I rarely find myself needing help isolating an issue. But anything that anyone can do to help would be tremendously appreciated.