Windows 11 is installed on a MBR disk, booted via Legacy BIOS, Grub2Win is installed in EFI mode

[Gianbernandini Spaccoso]

Hi there, i've been using your program for a long time (as i think you already know😂) and i've decided to upgrade my main PC to Windows 11 since Windows 10 EOL date is coming closer. I've just now reinstalled Grub2Win but it's detecting my PC booted with an EFI firmware, even if msinfo32 says it's booted via Legacy. Here below is attached the current not working diagnostic file of Grub2Win. I hope this will be fixed soon :]

[Drummer]

Hi,

The problem is that the Microsoft does not support Windows 11 in MBR / BIOS legacy mode.
Windows 10 was the last supported release for MBR / BIOS.

Grub2Win makes many calls to Microsoft libraries and functions. These often fail when running unsupported by Microsoft. Therefore Grub2Win does not work unsupported. Various functions crash in unusual ways or provide invalid information when run under Windows 11 unsupported.

Everything works fine in Windows 11 supported EFI mode.

May I ask the reason you are trying to install Windows 11 unsupported in legacy mode?
Your LG Laptop can easily run EFI.

Please let me know.

Thanks,

Dave

[Gianbernandini Spaccoso]

Hi there! First note is that i dont have an LG Laptop, this Windows install is running on an Acer Veriton S6620G motherboard, dated 2012 (so it's pretty old).
I installed Windows 11 via BIOS since this motherboard's firmware supports UEFI booting only for Windows 8 as far as i know, i've never got UEFI boot to work.
Is there a way to force the Grub2Win installation to BIOS mode instead of EFI via an argument of sorts? And if not, could it be done? I find myself better with using Linux because Windows doesn't run really well so i pretty much need it. If it cannot be done then i'll search for some other solution :)

[Drummer]

Hi again,

The diagnostics you sent me show the running machine is an LG 17Z90N with a Phoenix BIOS date of 02/02/2021. That's the reason I assumed you were running the LG.

I tested Grub2Win on Windows 11 unsupported MBR / BIOS and it crashes all over the place.

As I mentioned earlier, many Microsoft library calls fail or return invalid results when running Windows 11 unsupported. This crashes Grub2Win when attempting to install or run in this mode.
It simply doesn't work, and there is no way I can make it run without crashing.

When you installed Windows 11 MBR / BIOS you probably used Rufus or registry hacks.
At that point Microsoft warned that there might be incompatibilities and that the hacked install was not recommended.

I cannot rewrite the Microsoft libraries so I'm afraid this will not work for you.

Thanks again,

Dave