Re: grub-mkrescue: Problem with MBR partition table at start of EFI partition

[Thomas Schmitt]

Hi,

Florian Pelz wrote:
> Shall I continue testing?

I'm into ISO images. But it might be interesting to see what Microsoft
deems to be bootable and is willing to promote by its weight.


> I do not know how to verify on Windows if the boot used UEFI.

You could zeroize the x86 machine code in the MBR:

  dd if=/dev/zero bs=1 count=446 of=/dev/sdb

Then BIOS/CSM legacy mode should not have anything to start with.
(It would be interesting to know whether there is useful machine code
 in the MBR at all.)

Similarly you could rename the efi/boot directory in order to hide the
EFI start-up programs and thus to prevent EFI booting.


Have a nice day :)

Thomas