What are the supported UEFI configuration options

[Borden Rhodes <borden@bordenrhodes.com>]

Good afternoon,

I'm trying to build an image that uses grub-efi to boot, as MBRs are
getting less common and I want to use GRUB to dual-boot my image with
other images (yes, I've gotten this to work on a legacy BIOS install
using syslinux). During the build process, I get the following
warnings:
P: UEFI Secure Boot support enabled.
W: Bootloader in this image type not yet supported by live-build.
W: This would produce a not bootable image, aborting (FIXME).

And no image gets generated.

I have the following settings in my ./auto/config file:

lb config noauto \
        --apt aptitude \
        --architectures 'amd64' \
        --binary-images 'hdd' \
        --bootappend-live 'boot=live locales=en_CA.UTF-8
keyboard-layouts=us keyboard-variants=dvorak' \
        --bootloaders 'grub-efi' \
        --debian-installer 'true' \
        --distribution 'buster' \
        --linux-flavours 'amd64' \
        --memtest 'memtest86+' \
        --firmware-binary 'true' \
        --firmware-chroot 'true' \
        --archive-areas 'main contrib non-free' \
        --uefi-secure-boot 'enable' \
        --security 'true' \
        --updates 'true' \
        --backports 'true' \
        "${@}"

I can't find anything in the manpages which says which configuration
combinations are supported. Rather permute through every configuration
operation, it seems more efficient to ask.

With thanks,