[wesk05]

Please can you send me the output of:
cat /sys/class/amhdmitx/amhdmitx0/rawedid
Sam 

I don't think it has anything to do with the EDID. 12-bit YCbCr 4:2:2 works on the same display with the Shield, Zidoo X9S and even Minix U9-H Android. Vero 4K or Amlogic LE is not setting the pixel encoding to 422. It is being output as 444 (at < 4K 50Hz), which is why you get the green tint.