Hi, all! I have just made Apple TV work on Big Sur 11.1.
My machine is Z490 Vision D with i7 -10700 and GPU AMD RX 5700 XT.
My machine is set to iMac 20,2.
I have OpenCore 064.
I updated from Catalina, and my Apple TV didn't work. So I did some research,
and I did this.
I opened the command line, and I paste line by line, and pushed enter
these are the commands:
defaults write com.apple.AppleGVA gvaForceAMDKE -bool YES
defaults write com.apple.AppleGVA gvaForceAMDAVCEncode -bool YES
defaults write com.apple.AppleGVA gvaForceAMDAVCDecode -bool YES
defaults write com.apple.AppleGVA gvaForceAMDHEVCDecode -bool YES
After that Apple TV works.
I hope I help, but, before you do it, let some experienced users to answer my post. I don’t want to mess up your machine.