I don't really buy the noise cancelation mic issue here, I am a iphone tech at the ifix repair shop, and I have replaced the bottom mic(contained on the click and charge jack) and the top mic, and in most of the cases it fixes the problem for a short period of time before it just comes back and the mic no worky!! Sounds just like whats happening here, turn a screw here and there and the problem seems to be fixed, but then returns, all false positives. That audio IC has to be removed and re-balled and resoldered back onto the board for this problem to go away, so far I have only done 1 wich was successfull. keeping in mind I was re-balling by hand 0.2mm solder balls with a needle, hotair station and a magnifying glass. very intense work, takes about 2-3 hours. So to what I know this is really the only fix, keeping in mind that sometimes when you "reset all settings" on the phone it can also make the problem go away for a little while, so it's no surprise that turning some screws here and there will also...