Re: ISO installer image: GPT versus MBR partitions

[Thomas Schmitt]

Hi,

Florian Pelz wrote:
> my Macbook still does not like it.

The content of the EFI partition of guixsd-install-0.15.0.i686-linux.iso
does not look like it is ready for 64-bit x86:

  $ mount guixsd-install-0.15.0.i686-linux.iso /mnt/iso
  $ mount /mnt/iso/efi.img /mnt/fat
  $ find /mnt/fat -exec ls -ld '{}' ';'
  drwxr-xr-x 3 root root 7680 Jan  1  1970 /mnt/fat
  drwxr-xr-x 3 root root 1024 Jul  6  2018 /mnt/fat/efi
  drwxr-xr-x 2 root root 1024 Jul  6  2018 /mnt/fat/efi/boot
  -rwxr-xr-x 1 root root 96256 Jul  6  2018 /mnt/fat/efi/boot/boot.efi
  -rwxr-xr-x 1 root root 96256 Jul  6  2018 /mnt/fat/efi/boot/bootia32.efi

According to UEFI specs, bootia32.efi is the start program for 32-bit x86
systems.
The name for 64-bit x86 systems would be bootx64.efi like in the EFI
partition of debian-9.3.0-amd64-netinst.iso :

  drwxr-xr-x 3 root root 16384 Jan  1  1970 /mnt/fat
  drwxr-xr-x 3 root root 2048 Dec  9  2017 /mnt/fat/efi
  drwxr-xr-x 2 root root 2048 Dec  9  2017 /mnt/fat/efi/boot
  -rwxr-xr-x 1 root root 390656 Dec  9  2017 /mnt/fat/efi/boot/bootx64.efi

(Afaik, the EFI partition image is created by grub-mkimage. But i may
 be wrong. Better check source of debian-cd or ask Steve McIntyre.)

Was GRUB configured to produce 64-bit x86 code ?


I only know how to do it with Debian. There i have to install the
packages "grub-pc" for BIOS, "grub-efi-ia32-bin" for 32 bit x86 EFI,
"grub-efi-amd64-bin" for 64 bit x86 EFI.

The EFI partition then has:

  drwxr-xr-x 3 root root 7680 Jan  1  1970 /mnt/fat
  drwxr-xr-x 3 root root 1024 Feb  6  2016 /mnt/fat/efi
  drwxr-xr-x 2 root root 1024 Feb  6  2016 /mnt/fat/efi/boot
  -rwxr-xr-x 1 root root 132608 Feb  6  2016 /mnt/fat/efi/boot/bootx64.efi
  -rwxr-xr-x 1 root root 95744 Feb  6  2016 /mnt/fat/efi/boot/bootia32.efi
  -rwxr-xr-x 1 root root 95744 Feb  6  2016 /mnt/fat/efi/boot/boot.efi
  -rwxr-xr-x 1 root root 1759 Dec 10  2017 /mnt/fat/NvVars

("grub-pc" caused bootable MBR x85 code.)


Have a nice day :)

Thomas