"Check to see if you can record a voice memo...if not, What you are experiencing is a known issue and there are several posts concerning it. Reflowing will not fix this issue. You will need to remove U3101 Audio IC and run a jumper from the C12 pad.
"What is the version of the iPhone? Is it the issue that the aftermarket replacement not compatible with the iOS 11 just like the iOS 11 first time launched.
Update the device system to the newest.Remove the Home button and front facing camera flex cable then test the device boot up speed."
"I have an iPhone 7 that suddenly the microphone stopped working during texting. I have no damage to the phone and it has never been repaired / phone never opened. The phone takes 2-3 minutes to boot and flashes several times during the process. The VoiceMemos red button is greyed out (non functional), and when I call someone, the speaker icon is greyed out. I have sound from my speakers as normal. On the accessibility menu, I have no setting (just doesn't appear) for noise cancellation.
I am at iOS 11.3, this did not happen immediately after upgrading. I have reset, resinstalled, DFU'd every possible software thing. I have rebooted probaby 30 times now. One time the boot was fast (normal) and the mic worked as it did before.
It is like the mic subsystem is faulting on boot and is eventually shut down.
Any ideas? Any freeware diagnostic I can use to help troubleshoot?
What am I looking at if I take this in to Apple - I have had it about 1.5 or so years."
"I have the same problem as DeafeningSilence on my iPhone 7. Used 1.5years. Wtf is going on?!! Boot time is about 5min. Once I got it to work normally, booted normally, voice memo and calls working but then after couple calls it got fked up again. No sounds when calling ( no speaker option) and there is no sound when taking videos. YouTube and Spotify works normally though. Now I can call but nobody hears on the other line nor do I hear them. App calls like messenger or WhatsApp doesn’t even wanna connect neither through video calls . Even with WiFi/4g working properly.
Also when I connect headphones which are btw brand new the phone doesn’t recognise them. But then again.. by Connecting with Bluetooth headphones The phone seems to work normally.
I’ve Tried everything from restoring as new phone etc with no luck."
