Chosen Solution
There is a buzzing background noise on iPhone 7 front camera microphone. Other microphones works fine. I have tested with severeal flex cables, could this be a software issue?
Unless this issue only occurs with one app, I doubt it’s a software issue. Depending on where you got your FCAM flexes, it could also be a parts quality issue. Lastly, the iPhone 7 is known to suffer from Audio issues due to flexing of the logic board. At this point, you need to identify some known-good parts, logic board or housings and start swapping until a pattern emerges.
