[M-A8]

First of all my apologies for doing it so late, but originally (few months ago) I just completely forgot to do this straight after fixing this issue.

After 2 days with massive help from Del, Mannyo and PsYcHe we finally got to the bottom of this problem.

Some users with Bluetooth telephone and Voice Control have issues with following functions NOT working after MMI Update to ver. 5570:
- Microphone [telephone] (when connected via Bluetooth, caller can't hear you, but you can hear them)
- Voice Control (''Button Not In Use'' after pressing VC button on the steering wheel)

Solution is weird, but simple.

First go to [07] Control head and then CODING
Change coding to 0000002 --> Do It
Exit controller


Then go to [77] Telephone and then CODING
Change coding to 0010900 --> Do It
Exit Controller.


Exit VCDS and wait 30sec.

After 30sec REBOOT MMI by pressing ALL 3 buttons at the same time:
TEL + Selection Button + TOP RIGHT sub-menu button as per picture below


After reboot you should have everything back and working again as it should.

The trick is to tell the car if you have all this gizmos that you don't have them, weird, but this is Mannyo's explanation:

If you have voice control, then the microphone is connected to the Voice control module since it is possible to have voice control and no bluetooth.

You code the phone module without voice control because the voice control module is in effect controlling the infotainment (including the phone as it is part of the infotainment).

If you code the phone module for voice control, then the phone module will expect the microphone to be connected directly to itself, and it in turn would then handle the voice control. As a side effect, since voice control is now listening through the bluetooth module without a microphone, the whole thing stops working.

So far Me, RicharRacer and Scott had this exact same problem and in all 3 cases this solved both issues.

I hope more people will find this helpful ++