Support UEFI 32bit boot on amd64 #227
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We dropped support for i386, though there are 32bit EFI systems with 64bit CPUs out in the wild, so let's support UEFI 32bit boot on amd64. Verified with /usr/share/OVMF/OVMF32_CODE_4M.fd from ovmf-ia32 (v2024.11-2) and qemu, running: % qemu-system-amd64 -m 2048 -M pc -cdrom /path/to/grml_isos/grml_0.42iso -drive if=pflash,format=raw,unit=0,file.filename=/usr/share/OVMF/OVMF32_CODE_4M.fd,file.locking=off,readonly=on Launch boot UEFI interactive shell there and verified that this works: fs0: cd efi/boot bootia32.efi This shows the Grml boot menu as expected, whereas executing bootx64.efi fails (as we're running within a 32bit EFI environment), also as expected. NOTE: We already ship the grub-efi-ia32-bin package on AMD64 already for support within /etc/grml/fai/config/scripts/GRMLBASE/45-grub-images. But for netboot package we need the grubnetia32.efi for usage as grubia32.efi. Though the file /usr/lib/grub/i386-efi-signed/grubnetia32.efi.signed is shipped only via the grub-efi-ia32-signed package, which is available only on i386. Therefore we need to use the file /usr/lib/grub/i386-efi/monolithic/grubnetia32.efi from grub-efi-ia32-unsigned instead, which is available only as of Debian/trixie and newer. But let's still provide the code path in netboot creation, as someone might handle this within a custom script on their own. See grml/grml#211
zeha
approved these changes
Dec 19, 2024
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We dropped support for i386, though there are 32bit EFI systems with 64bit CPUs out in the wild, so let's support UEFI 32bit boot on amd64.
Verified with
/usr/share/OVMF/OVMF32_CODE_4M.fdfrom ovmf-ia32 (v2024.11-2) and qemu, running:Launch boot UEFI interactive shell there and verified that this works:
This shows the Grml boot menu as expected, whereas executing bootx64.efi fails (as we're running within a 32bit EFI environment), also as expected.
NOTE: We already ship the grub-efi-ia32-bin package on AMD64 already for support within /etc/grml/fai/config/scripts/GRMLBASE/45-grub-images. But for netboot package we need the grubnetia32.efi for usage as grubia32.efi. Though the file /usr/lib/grub/i386-efi-signed/grubnetia32.efi.signed is shipped only via the grub-efi-ia32-signed package, which is available only on i386. Therefore we need to use the file /usr/lib/grub/i386-efi/monolithic/grubnetia32.efi from grub-efi-ia32-unsigned instead, which is available only as of Debian/trixie and newer. But let's still provide the code path in netboot creation, as someone might handle this within a custom script on their own.
See grml/grml#211