MacBook Pro 16"
Core i7-9750H @ 2.6GHZ
16GB Ram @ 2666MHZ
AMD Radeon Pro 5300M
AMD Radeon 6900XT
Windows10 20H2 - 19042.631
Radeon Software 20.12.1 (2020, Dec) - bootcampdrivers.com
1. Install Windows in bootcamp
2. Install the driver that comes with bootcamp
3. Turn off or pause automatic updates
I did not uninstall the sound card driver, DDU is using the default configuration.
5. After installing the driver, reboot into MacOS
6. [EFI Loader] Error 12 Fix in Boot Camp for Apple T2 Security Chip Macs (apple_set_os loader v0.5) | BootCamp eGPU Setup Follow the steps within this post to modify the EFI file.
7. After modifying the EFI file, turn off your computer and then plug the eGPU into the left usb port.
8. your computer will automatically boot up and boot windows. you will see that the modified EFI file has taken effect, then press any key to enter the system. You will feel that the boot-up speed is significantly slower.
9. When windows loads to the desktop (you can see the icon of the application on the desktop), unplug the eGPU and reinsert the eGPU in the right usb port.
Note that the egpu is switched from the left to the right side of the computer
10.Wait 15~20 seconds, then unplug the egpu and plug it back into the left port where it was previously plugged in.
You can actually use the official driver, but the dGPU won't work. Also I disabled the iGPU in Device Manager.
I updated macOS to 11.3 beta5 but still can't drive the 6900XT.
Can I ask how many GB ram does your video card have? Your build is the first I've seen running Big Sur w/ any version of Windows newer than 1903. I'm trying to figure out if apple_set_os loader works for Big Sur and newer versions of win10. Seems like it does for you - so that's great news!