My nephew's phone is having a weird issue. I'll make this as short as possible: The microphone works 100% fine when using Siri, Voice Recording, Talk to text, etc but does not work whatsoever during a phone call; nobody can hear you saying anything at all when you call them from this phone. What is going on here? My thought was that Siri and such uses the noise cancelling mic at the top, so maybe the bottom microphone is broken (so doesn't work when making a phone call), but everything else works because it's a different mic? Not the issue, though, since Voice Recorder uses the bottom microphone and I've even blown into it while recording and all I can hear is the sound of air being blown into the mic. Any ideas what's going on? I plan to replace the bottom assembly where the mic is located, but I don't really understand why I'd do that seeing as I've already confirmed that the mic down there is fine. I just have no idea what's happening here. How can the mic work fine, but turn itself off only during phonecalls?