I did a factory reset and that helped it somewhat with the mic, the recorder finally worked but the mic still did not work during calls, minus speakerphone/headset, not even going back to the official stable rom helped.
I've recently got my hands on an Mi3 but I have noticed that the microphone doesn't work properly during calls, they don't hear me at all, just some noise but it works fine if I turn on the speaker, same if I use the recorder, just noise.
Using the latest developer ROM.
Sent from my MI 3W using...