After looking through at least 50 pictures of power/speaker harness for similar units to F9220BT I found the solution!
BYPASS FOR PIONEER AVIC-F9220BT:
First of all move the mute wire as described in a lot of these forums - just like SoundMan describes here:
or as shown on the picture below:
Here comes the tricky part. The parking brake wire.
I have a quadlock plug-and-play harness which doesn't have a light green wire! Or it have one (left in picture) but it doesn't have an effect to ground it together with the mute.
What I did was to use the white wire and ground it togethe