Re: grub-mkrescue does not boot on older Macs as USBstick

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Alexander E. Patrakov wrote:
> The first thought, though, is related to the fact that the Porteus Kiosk
> image uses partitions aligned to 1 MB. It may be a good idea to force this
> on grub-mkrescue command line and test-boot the result.

That would be xorriso -as mkisofs options

  -partition_cyl_align on -partition_hd_cyl 64 -partition_sec_hd 32


Did you note the embedded configuration snippet at the end of
the file /EFI/BOOT/bootx64.efi in the Porteus EFI partition ?

  search --file --set=root /docs/kiosk.sgn
  set prefix=($root)/boot/isolinux/efi

(One should not get confused by the directory name "isolinux".)

Your "minimal.iso" does not have such strings in its bootx64.efi
or bootia32.efi.

In bootia32.efi of debian-8.2.0-i386-netinst.iso :

  search --file --set=root /.disk/info
  set prefix=($root)/boot/grub
  source $prefix/i386-efi/grub.cfg

In bootx64.efi of debian-8.1.0-amd64-netinst.iso :

  search --file --set=root /.disk/info
  set prefix=($root)/boot/grub
  source $prefix/x86_64-efi/grub.cfg

They all search for files in the ISO, not in the EFI partition.
I understand Debian hops onto the ISO's GRUB2 config for menu display.
(Does Porteus just boot a kernel without further menu ?)


Have a nice day :)

Thomas