Bug#1026092: grub-efi-arm64: grub2 needs a backport to support EFI zboot

[Ard Biesheuvel]

Package: grub-efi-arm64
Version: 2.06-5
Severity: wishlist
X-Debbugs-Cc: ardb at kernel.org

Dear Maintainer,

Linux 6.1 and later implement a EFI bootable compressed format called zboot,
which does not carry the 'arm64 bare metal boot' magic number because it is
EFI-only and cannot be booted in bare metal mode unless the bare metal
loader knows how to decode the header and perform the decompression itself.

None of this is relevant to GRUB, as it is pure EFI based on arm64. However,
it used to check the magic number nonetheless, rejecting these EFI zboot images
for no good reason.

This is fixed in GRUB upstream by
https://git.savannah.gnu.org/cgit/grub.git/commit/?id=69edb31205602c29293a8c6e67363bba2a4a1e66

Please consider this change for backporting to Debian's GRUB so arm64 builds
can boot the EFI zboot images.

Kind regards and merry christmas,