[EFI Loader] Error 12 Fix in Boot Camp for Apple T2 Security Chip Macs (apple_set_os loader v0.5)
Hello guys, I modified 0xbb's apple_set_os.efi to make it easier to use eGPU on the new MacBook Pro 16". I noticed the old efi doesn't always load successfully so I made this version. In this version, if apple_set_os isn't loaded, it will restart the computer automatically so it will save you some time. Once apple_set_os is loaded, it will start the boot loader of your choice.
Installation and usage instructions
Works!! On the first attempt it took three restarts, but second time it worked with one. One thing that I noticed was that my internal display was not starting up. It was showing the windows logo and loading animation and then it would go completely black. It might be because in windows display settings I have disconnected this display (use laptop in clam-shell mode). But this is not an issue for me because I don't have a password, so when I see the controls appear on the touchbar, I do the tb3 port swap thing (left -> right -> left) and everything works!
Enjoying Forza Horizon 4 (4k - High) thanks to you.
Could it work on iMac 21,5' 2017 too?
Because I never succeeded to load previous EFI boot with this iMac (when I select the OS, it freezes).
@aa15032261 Thank you for sharing this nice solution! Do you see the Intel iGPU in Windows using this solution?
@aa15032261 That's good to hear. The Intel iGPU actually doesn't work on 2018-2019 15" & 16" MacBook Pro but can be force-enabled through apple_set_os.efi and rEFInd. When you attach it to the internal display, the screen would show tiny circle dots and go dark. As long as the dGPU works, Windows Hybrid graphics can use eGPU for internal display acceleration if needed.
I am curious about these recent developments and apple_set_os.efi behaviors with Boot Camp eGPU use. Some early releases of Catalina contain firmware updates (Apple T2 chip Macs only) that completely ignore iGPU force-activation by apple_set_os.efi and rEFInd. I have observed the latest 10.15.2 and 10.15.3 beta to somewhat work with apple_set_os.efi and rEFInd again. However the latest firmware updates mess with Thunderbolt connection state in Windows.
I typically test Thunderbolt 3 connection during Windows boot up process using a TB3 enclosure with RGB, not for the lighting effects but for Thunderbolt connection state monitoring. Take the Razer Core V2 for example, at cold boot the RBG turns on with the connected laptop. During pre-boot, boot loader, and initial OS loading the RBG remains on. The second half of OS loading is when the RBG turns off. If the RGB turns back on when OS loading completes, Thunderbolt connection is active. Otherwise Thunderbolt connection is not active and would require hot-unplug then hot-plug to make the Thunderbolt connection active.
My guess is you may be able to boot into Windows without the eGPU connected using this solution. Try hot-plug your Radeon VII eGPU once Windows fully loads and see whether the system can resolve error 12.