secure boot disabled csm fails on older uefi system

A

Autochthon

Limp Gawd
Joined
Apr 28, 2005
Messages
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I decided to move an older setup to use secure boot and I'm having some difficulties.

motherboard asrock z68 Fatality Professional gen 3; 2.23 bios slightly customized to allow nvme boot from pci slot.
2600K Sandybridge @ 4.3 ; 16G (2x8) mem
samsung 840 pro 256G ssd using GPT
gigbyte 650 ti windforce OC 2GB

both MB and video card are right on the transitional edge of UEFI systems

So I have this system booting windows 10 pro and linux mint 21 in UEFI and all is fine.

I disable csm in the uefi setup and try to boot windows. The boot screen pops up, the little circle of dots does a half circle and hangs;
30 sec later the system blue screens with a "machine exception error".

If I boot into Mint, it boots but the video driver doesn't appear to load correctly as only one (of 2) monitor(s) activates. driver manager says proper nvidia driver is loaded.

I blamed all of this on my video card not being uefi compatible so I checked using GpuZ and sure enough it wasn't. But I found that a newer bios for the card was UEFI compatible.
I flashed the newer bios and GpuZ verified that is was now UEFI. When I tried Mint with secure boot enabled it verified that secure boot was enabled.
I tried booting using rEFInd (a third party boot manager) and it also verified secure boot but the behaviour in both Windows and Mint was unchanged (machine exception windows and borked video mint).

So am I missing something? My pessimistic guess is that the video card isn't really UEFI compatible despite the newer bios and I'm out of luck.
Anyone have a similar experience or a recommendation to get this working?

thanks all
 
only point of secureboot is if youre running bitlocker, or using a third-party updateb system
 
pendragon1 said:
so you modded the bios and not it doesnt work right?! put it back to stock maybe...
you could try: Convert an existing Windows 10 Installation from Legacy BIOS to UEFI - Microsoft Community
Click to expand...
I modded the bios years ago to allow me to boot from an NVME drive. That works fine and never caused me any problems that I'm aware of.

I can boot from UEFI just fine, boot drives are UEFI and GPT and I boot from an ESP partition for windows boot manager (bootmgfw.efi) or Linux mint boot partition (shimx64.efi->grubx64.efi) or rEFInd(shimx64.efi->refindx64.efi) which just allows me to choose my boot loader if I want that flexibility.

The errors just arises when I disable csm.

edit:
I had used mbr2gpt.exe to do the original conversion to GPT and all seemed fine except for secureboot.
 
Last edited:
Autochthon said:
I modded the bios years ago to allow me to boot from an NVME drive. That works fine and never caused me any problems that I'm aware of.

I can boot from UEFI just fine, boot drives are UEFI and GPT and I boot from an ESP partition for windows boot manager (bootmgfw.efi) or Linux mint boot partition (shimx64.efi->grubx64.efi) or rEFInd(shimx64.efi->refindx64.efi) which just allows me to choose my boot loader if I want that flexibility.

The errors just arises when I disable csm.

edit:
I had used mbr2gpt.exe to do the original conversion to GPT and all seemed fine except for secureboot.
Click to expand...
k, i might have been misunderstanding. you might need something like grub to do all that.
 
Yeah it won't even boot an installation or recovery disk for windows same error. Something about that "bootmgfw.efi" doesn't work with this system with csm disabled.
 
Well I trashed my system in the process but I managed to get secure boot active in both linux and win10. Apparently this ASRock bios is a bit different. If csm is disabled it breaks the boot (at least for windows). But you can still activate secure boot with csm enabled. This is opposite of what I had read elsewhere and opposite of all of my other systems. ;/
 
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