From what I know it’s not about the resolution but the codec. UHD in H.264 gets handed over correctly to Hyperion but UHD (or FullHD, for that matter) in H.265 will give you green/coloured nonsense. I think it has to do with the chip the Vero uses.
This matter is discussed somewhere in the huge Hyperion thread but I can’t remember which of the nearly 700 posts.