Thomas Schmitt wrote:
>
>On an amd64 system i can get UEFI equipment in a grub-mkrescue ISO
>by installing binary packages grub-efi-amd64-bin and/or grub-efi-ia32-bin.
>This can be further combined with grub-pc-bin for PC-BIOS.
>Then i run grub-mkrescue with a dummy payload directory instead of a
>directory tree with operating system files:
>
> mkdir minimal
> grub-mkrescue -o output.iso minimal
>
>The result should then have EFI System Partition and El Torito image in
>personal union, containing start programs for i386 and/or amd64.
>Further there should be bootable MBR code and El Torito image for PC-BIOS.
>Partition table is GPT. Have a look at Guix ISOs which get built by
>grub-mkrescue. (There is also HFS+/APM stuff for antique x86 Macs.)
>
>The Volume Id of the Hurd ISO from june 2017 looks like debian-cd
> Volume Id : Debian sid h-i386 n
>But it has GRUB equipment for PC-BIOS rather than the usual ISOLINUX.
>Well, debian-cd is flexible.
>If it's that what you are using, let's talk to Steve McIntyre when he is
>done with converting Jigdo to SHA256.
>
>Whatever, it will be not a big obstacle to develop a xorriso run if
>you have all GRUB equipment ready for EFI. It may also be a good
>opportunity to switch to grub-mkrescue for ISO generation (and my wrapper
>script for making MBR partitions rather than GPT).
>
>--------------------------------------------------------------------------
>
>I cannot say whether there is nothing which the Mach kernel would want from
>the firmware. Maybe ask Steve McIntyre whether he had to wait for special
>Linux precautions before being able to boot amd64 via EFI (long ago).
There's a few pieces to think about here, from reading the thread:
1. adding UEFI support in debian-cd for the hurd-i386 CD
build. That's easy
2. If you're going to test-boot that in a qemu VM, you'll need a
32-bit OVMF build to test it too. Thet 64-bit OVMF in the archive
will only boot a 64-bit kernel. I have a 32-bit binary build I use
myself for local testing in git at
https://git.einval.com/cgi-bin/gitweb.cgi?p=efitest.git
in case that helps
3. Finally (the elephant in the room) - booting via UEFI is not the
same as BIOS boot. The entry points are different (for a start),
and there are quite a lot og kernel changes needed to support UEFI
initialisation etc. I've not heard anything about people working
on this for Hurd at all.
--
Steve McIntyre, Cambridge, UK. st...@einval.com
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