On an X85 series television will it just be a matter of a software update to make the built-in Chromecast support 4k and HDR - like a Chromecast Ultra: or does it already have these abilities: or will I have to disable the internal Chromecast and buy a Chromecast Ultra?
Will most likely require a Google Cast update AND a Firmware on the TV. My LG TV was made HDR compatible through a firmware update.
What I don't understand is why they don't use the embedded ethernet channel in HDMI instead of using an adapter for ethernet. This would make it even more efficient.
Great question, I'd like to know too. The installed version of Google Cast Receiver on my X750D (running Android TV 6.0.1) is 1.20.67611, and it's an updateable app, so hopefully this means Google can update it, and I won't need to wait for Sony. Sony seems to be terrible with their update schedule.
Obviously my set already supports 4K and HDR, so hopefully Google pushes that update to these sets too, so we don't need a largely redundant Chromecast if we want 4K/HDR.
Sorry, no useful answer I can offer except to say this is why I hate smart TVs and have avoided them. I trust them even less than phone carriers to do what it takes to keep software patches up to date for just about anything.