I have UI3 running occasionally on both the XBox and the FireStick on two different TVs. This AM I looked at the rarely-used XBox session, and it was crystal clear, with no periodic flickering as seen on the FireStick. The session pop-up said it was using 'jpeg HD'. I looked at the session profiles, and all the 4K, 2K, etc, profiles above the 'jpeg HD' were colored in red. Cool! So I went to the FireStick on the other TV, and was unable to use the Amazon remote to 'click and drag' the preferred 'jpeg HD' to the top of the list. I then started deleting all the top list H.234 profiles one by one, and saw where the picture quality continued to degrade as the profiles were being deleted and favoring the lesser quality sessions. When finally the preferred 'jpeg HD' came to the top of the list, the picture quality became crystal clear, with no more periodic flicker and pixilation.