I have a similar build but till now I didn't manage to make it works any help would be appreciated .I am on Ga-EX58-UD3R (differences on our mob I think is only the audio alc888 vs alc889) with an i7-920 LGA1366 and a Nvidia GeForce GT 710 .
I am using opencore 0.6.4 ,the usb stick boots just finely am getting in the installer, format the new disk as APFS but 12 minutes before finishing every time, I am getting unable to get fs for /Volumes/MyVolume/Macos install data and then after a few lines in the installer log the system hangs and reboot.
So I thought ok, in Catalina as well with clover I was getting 2-3 restarts before the end of the installation and after choosing the new partition the installation kept going.
In this case after the restart , I boot from the usb again and i chose the apfs HDD with the name now bigsur installer. Choosing this gives me a kernel panic after a few commands and the system restarts. Photo
Here is MYEFI
We have very similar builds so maybe it's possible to install BigSur in this old guard.I don't thing it's an EFI issue or opencore config error because the system boots till the installer fine, no error.The installation begins and 12 minutes before the end (at that point boot loader doesn't have a lot to do with the whole procedure ) it fails.
I don't want to hijack your thread, shall I open another one ?