Hi Thomas...
Thanks for detailed response. This is very helpful. So, if I understand correctly, I should probably build the image with both grub-pc and isolinux configuration folders in config/bootloaders, and they will automatically be selected up in 32-bit and 64-bit
hardware?
Best regards.
From: Thomas Schmitt <scdbackup@gmx.net>
Sent: Wednesday, December 8, 2021 10:00 PM To: debian-live@lists.debian.org <debian-live@lists.debian.org> Subject: Re: Building image with grub-efi-amd64 instead of grub-pc? Hi,
Anindya Chaudhuri wrote: > > I would like to use grub-efi-amd64 instead of grub-pc Elias Mobery wrote > Live-build uses syslinux as default bootloader. It will be able to > boot both uefi and legacy without any additional modifications. As developer of xorriso i can state that both GRUB boot equipments are combinable, and that the SYSLINUX equipment that gets built into the ISO is for legacy BIOS only. (Actually SYSLINUX EFI does not boot from CD or DVD by most real iron firmwares. OVMF might work because it tends to take the code path for partitioned disk devices.) SYSLINUX/ISOLINUX legacy BIOS equipment is often combined with GRUB for EFI. This seems to be the case with live-build for "syslinux" plus "grub-efi". --------------------------------------------------------------------- Reasoning: Whatever gets prepared, it has to be announced to the xorriso run in order to get into effect. I see in https://sources.debian.org/src/live-build/1:20210902/scripts/build/binary_iso/?#L117 the xorriso options for legacy BIOS with LB_BOOTLOADER_BIOS="grub-pc". In https://sources.debian.org/src/live-build/1:20210902/scripts/build/binary_iso/?#L146 i see the xorriso options for EFI with LB_BOOTLOADER_EFI="grub-efi". The distinction between 32 and 64 bit x86 EFI is probably made when the EFI system partition image boot/grub/efi.img gets composed. In https://sources.debian.org/src/live-build/1:20210902/scripts/build/binary_grub-efi/?#69 and following lines i see indications that this choice depends on variable LB_ARCHITECTURE. So everything seems to be prepared for the combination of both kinds of boot equipment on ISOs for amd64 (or i386). To corroborate my assessment about SYSLINUX: There is no mentioning of EFI in https://sources.debian.org/src/live-build/1:20210902/scripts/build/binary_syslinux/ The script https://sources.debian.org/src/live-build/1:20210902/scripts/build/efi-image/ has echo "usage: $0 OUTPUT-DIRECTORY GRUB-PLATFORM EFI-NAME NETBOOT-PREFIX" and seems to be generally addicted to GRUB. Have a nice day :) Thomas |