We're working on getting Kali to work as a VM on the Apple M1 and so we
are trying to build arm64 installer images with simple-cdd (and thus
debina-cd). In this process, Steev Klimaszewski <steev@kali.org>
discovered that the grub configuration used for the EFI boot on arm64 does
not take advantage of any theming, contrary to amd64/i386.

It would be nice if we could fix this by enabling the grub theme
everywhere. However this doesn't look entirely trivial as the theming
is handled through a mixture of code in tools/boot/bullseye/boot-x86
and tools/boot/bullseye/parse_isolinux, and arm64 is not relying on
isolinux at all.

Steve, your input is thus most welcome.