I tried with Mojave booted natively and the two movies in question will open and play for a second or two then stop with a black screen.He may need to replace any bridges in the path of the GPU with an SSDT so whatevergreen can perform the hooks. Anything greater than RX-580 has a borked device path in this respect and that is why the boot arguments work, but device properties don't.
Would I still have HDCP issues in a natively booted Mojave? Is there anything I can look for in iORegistryExplorer to identify issues?
Appreciate all the help as I'm feeling my way here.
Regards,
sfalatko