UEFI та live ISO

sgdisk --zap-all /dev/sda
sgdisk --new=1:0:0 --typecode=1:ef00 /dev/sda
mkfs.vfat -F32 -n UBUNTU /dev/sda1

mount /dev/sda1 /mnt/flash
mkdir -p /mnt/flash/EFI/BOOT
cd /mnt/flash/EFI/BOOT

wget https://releases.ubuntu.com/20.04.3/ubuntu-20.04.3-desktop-amd64.iso

cat - > grub.cfg <<'CONFIG'
menuentry "Ubuntu 20.04 LTS" {
    set isofile="ubuntu-20.04.3-desktop-amd64.iso"
    loopback loop (hd0,gpt1)/EFI/BOOT/$isofile
    linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/EFI/BOOT/$isofile noprompt noeject quiet splash
    initrd (loop)/casper/initrd
}
CONFIG

# А тепер якась дичина

grub-mkimage -o bootx64.efi -p /efi/boot -O x86_64-efi \
    fat iso9660 part_gpt part_msdos \
    normal boot linux configfile loopback chain \
    efifwsetup efi_gop efi_uga \
    ls search search_label search_fs_uuid search_fs_file \
    gfxterm gfxterm_background gfxterm_menu test all_video loadenv \
    exfat ext2 ntfs btrfs hfsplus udf