Hi I have this problem, now, I do not understand why this is happening with my motherboard. it used to be easy to install OSX Big Sur. but it will not boot up any of the OS already installed and neither can install a new copy of OSX.
I have checked the bios and followed recommendation. Still not able to boot or install new OSX. I have followed your instructions and used your EFI.
AMD Ryzen 5900
IMG_8358.zip