ASUS X99-A: Failed to write ReBarState UEFI variable, GetLastError: 5

[xfstef]

Hello!

I've been on a several day long journey of trying to enable ReBAR on my X99-A mobo with a 5930k and 64GB of DDR4 2133 running with XMP at 3200mhz in quad channel.

Reading and flashing the BIOS was difficult enough but I have managed with the help of AFUDOS and a guide that says to use the /GAN command.

I can confirm that my BIOS has the dxe driver added to it. 4G Decoding is enabled and CSM disabled.
Secure boot however is enabled. I hope this isn't the issue.

So when I run ReBarState.exe under an admin Command Prompt for Developer, I get the following error regardless of what value I choose:
Failed to write ReBarState UEFI variable
GetLastError: 5
You can close the app now

I have tried to reduce my RAM size down to dual channel 32GB, still nothing. I could try to go even further down if you guys think it could be an issue.

Right now I'm stuck, I have gone through every discussion and issue on here to make sure the answer isn't somewhere else.

I'd love some help / feedback. Thanks!

[xfstef]

I had to add the NVRAM access patch. Works now although when set to unlimited it allocates 16GB Rebar when my B580 only has 12GB. This causes stutters and makes most 3D games unplayable.
I have reduced the Rebar down to just 8GB but now my Intel drivers don't see Rebar as activated, will try a clean reinstall of the drivers.