@djnice Please test again with this update:
EDIT:
Please ensure again all is set to auto!
Boot, start your media for a few seconds then stop (keyboard x if nothing on screen).
Then dmesg | paste again please.
It should now boot in GUI 420, 12bit.
On DV start it should switch to RGB, 8bit.
After stop in GUI it should be 420, 12bit again.
Maybe…