System doesn't boot on UEFI-only systems

[James-Livesey]

x86-64 computers that run LiveG OS will boot the system in legacy mode instead of UEFI. We need to allow booting using UEFI by correctly building the ISO for the right GRUB version using grub-mkrescue.

[James-Livesey]

Probably best to look at Debian's xorriso arguments to allow UEFI and BIOS booting: https://wiki.debian.org/RepackBootableISO#:~:text=equipment%20actually%20works.-,Learn%20about%20the%20actually%20used%20ISO%20production%20command,-The%20Debian%20installation

xorriso -as mkisofs -r -checksum_algorithm_iso md5,sha1,sha256,sha512
-V 'Debian 9.3.0 amd64 n'
-o /srv/cdbuilder.debian.org/dst/deb-cd/out/2amd64/debian-9.3.0-amd64-NETINST-1.iso
-jigdo-jigdo /srv/cdbuilder.debian.org/dst/deb-cd/out/2amd64/debian-9.3.0-amd64-NETINST-1.jigdo
-jigdo-template /srv/cdbuilder.debian.org/dst/deb-cd/out/2amd64/debian-9.3.0-amd64-NETINST-1.template
-jigdo-map Debian=/srv/cdbuilder.debian.org/src/ftp/debian/ -jigdo-exclude boot1
-md5-list /srv/cdbuilder.debian.org/src/deb-cd/tmp/2amd64/stretch/md5-check
-jigdo-min-file-size 1024 -jigdo-exclude 'README*' -jigdo-exclude /doc/
-jigdo-exclude /md5sum.txt -jigdo-exclude /.disk/ -jigdo-exclude /pics/
-jigdo-exclude 'Release*' -jigdo-exclude 'Packages*' -jigdo-exclude 'Sources*'
-J -J -joliet-long -cache-inodes
-isohybrid-mbr syslinux/usr/lib/ISOLINUX/isohdpfx.bin -b isolinux/isolinux.bin
-c isolinux/boot.cat -boot-load-size 4 -boot-info-table -no-emul-boot
-eltorito-alt-boot -e boot/grub/efi.img -no-emul-boot -isohybrid-gpt-basdat
-isohybrid-apm-hfsplus boot1 CD1