I don't know much about those machines, or their keyboards, but it seems unlikely that they'd bother to come up with a different protocol for the keyboard other than "USB with a different connector."
At the point that the Grub menu is active there is extremely limited support for hardware: no operating system has been loaded. Support has to come from the BIOS/UEFI, and they generally have an option exactly for handling USB devices without an OS, called "Legacy USB Support" or something similar.
On UEFI devices you can reboot into the UEFI setup with
Code:
sudo systemctl reboot --firmware-setup
It may also be possible to use a similar command to boot into a different EFI entry, but that's not something I've ever tried to do.
Bookmarks