Mic not working after replacement

Hello,

So I have an iPhone 4 that I currently cannot get the mic to work. I have tried replacing the bottom mic and the top mic to no avail. I have read a lot of forums that say it could be software (currently 7.1.1) does anyone know any possible fixes for this problem?

Things I already tried:

Soft reset

Hard reset

Complete restore

Changing charge port (dock connector)

Changing headphone jack with top mic attached.

Changing the bottom loudspeaker.

Cleaning out the top mic hole.

If anyone has any advice it would be greatly appreciated.