I got this to work for an ASUS Z97M-PLUS. No USB Flashback on this board, the patched BIOS had to be updated the hard way. Finding a way to flash the modded BIOS was a drag. I ended up flashing it from within a running Windows 10.
For those who wondered (I did
): using an old and ancient BIOS with a working NvramSmi driver didn't do the trick. At least not for me. Not sure why.
Behaviour before patching:
I could start the installation USB with OC 0.6.5 I created using the Dortania guide, format my destination drive using Diskutil from the MacOS installer, then start the installation of Big Sur. When the slider was down to apprx 12%, the system rebooted and there was no bootable "MacOS Installer" entry for the freshly installed MacOS on the destination drive when I entered the OC boot menu again (the menu options were exactly the same as before the installation). I guess the installer somewhere crashed and didn't finished the first install pass in full.
What worked for me:
- Download the Z97M-PLUS-ASUS-2903.CAP and Z97M-PLUS-ASUS-2202.CAP file from the ASUS website. 2903 is the latest BIOS, 2202 contains a working NvramSmi driver.
- Use the older UEFITool_0.21.5_osx (as the latest NE A58 can't save) to patch the NvramSmi driver, as described by Blazinsmokey in the first post of this thread.
- Install and boot Win10 on a SATA SSD attached to the Z97M-PLUS.
- Use the 'procedure' part in this old post by Fernando to flash the BIOS. I used the part: B. Methods for ASUS mainboards without USB Flashback support, Using the AMI tool AFUWIN.
- For this, I removed the encapsulation from the patched 2903.CAP file using UEFITool_0.21.5_osx.
- I used AFUWIN64 tool v3.05.04 to first flash the standard 2903.CAP (without options), then the patched 2903.rom (with /GAN option).
- After flashing the patched rom version, I rebooted.
Behaviour after patching:
I did the same installation as before. After the first reboot, two extra boot options were visible in the OC boot menu: MacOS Installer and Recovery. The MacOS Installer was the default boot option, so the installation automatically continued as it should.
Thanks Blazin, for this thread! Saved me from tossing away this board and replacing it with a new one!