Add support to boot the Grub bootloader from an EFI BIOS in the ISO9660
image.
For that we need to create EFI System Partition (ESP). The ESP is a vfat
partition which contain the Grub2 binary at the /EFI/BOOT/ location.
xorriso command will generate the iso image including the ESP.
We notice Grub can not read and mount the ESP, therefore we place the Grub
configuration file in the ISO9660 partition. A Grub2 builtin configuration
need to be used to tell Grub2 to search automatically its configuration
file in the ISO9660 partition. Use 'set root=(cd0)' in the configuration
file passed to BR2_TARGET_GRUB2_BUILTIN_CONFIG_EFI.
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
[yann.morin.1998@free.fr: fix timestamp fixup hook]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
179ae068eb