Just received a Pi 4 2Gb kit from PiHut this afternoon and have followed the official Raspbian full setup documentation on the Raspberrypi website.
Once all that was done and working, I have attempted to follow the instructions in the first post using the armhf.deb file downloaded via chromium to home/pi/Downloads.
I ran "sudo apt install -f /home/pi/Downloads/emby-theater_3.0.11_armhf.deb" and it appeared to do stuff in the command window and then ran "sudo rpi-update" and
Once re-booted, I can run Emby-Theater directly from the Run command or from Menu | Accessories | Emby Theater and I mostly get a completely blank white screen and occasionally get a black screen with the Emby logo. That's it - nothing else!!! Not much use really.
If I navigate to the Server Dashboard in Chromium then I can see my libraries and even select a movie to play which it does in the browser.
Clearly being a Windows software developer I have missed something with the linux'isms of the instructions. Any help would be appreciated.