Re: [PATCH] core/partmap: Add El Torito boot catalog parsing

[Andrei Borzenkov <arvidjaar@gmail.com>]

В Sun,  7 Jun 2015 11:24:46 +0100
Ross Lagerwall <rosslagerwall@gmail.com> пишет:

> Add a module, part_eltorito, to allow parsing of the El Torito boot
> catalog into partitions. This follows the El Torito Bootable CD-ROM
> Format Specification Version 1.0 and the UEFI Specification 2.5.
> In cases where the specification is unclear, the code follows the UEFI
> reference implementation.
> 
> This is useful when booting CDs in UEFI mode. Before, GRUB would not be
> able to use the embedded ESP from which it was executed, so it would
> have a root and prefix set to the top level of the CD. This could result
> in subtle configuration bugs, because the same ISO booted from a USB
> disk (using isohybrid) would have its root and prefix set to the
> embedded ESP because it can find it through the MBR.

You can already access ESP on hybrid image using e.g. (cd0,msdos1); why
is it not enough?

> With this change, GRUB is able to access the embedded ESP and set its
> root and prefix correctly when booting a CD in UEFI mode. It also
> allows GRUB to access embedded floppy and HDD images.
>