Can anyone tell me if you are able to get around the problem using HA Cast as is described here: Cast - Size of Cards too big on Full HD Screen? I have this same problem. I see in the CATT page, it says “The display resolution is 1280x720.” On mine, it appears to be more like 720x1280, because it looks nearly the same as on an iPad in portrait mode, showing white bars on either side of the screen. Since I have a 4k screen and a Chromecast Ultra, this is just unacceptable.