Re: [PATCH 0/3] Add support for EFI file system transposition

[Thomas Schmitt]

Hi,

Pete Batard wrote:
> 2. It uses a efi.img to embed the UEFI bootloaders, but does not keep a copy
> of these bootloaders on the ISO9660 file system itself, with the end result
> that, when copying the media at the file system level, the '/efi/boot/'
> directory and its content is missing.

I understand why this is desirable for the use case of preparing a
grub-mkrescue USB stick on MS-Windows.
Insofar i support the duplication of the FAT image content in the ISO 9660
filesystem.


> we will point out that we consider it
> should really be the job of xorriso, rather than grub-mkrescue, to
> accomplish this duplication (hence why I am CC'ing Thomas), but we don't
> know the technical difficulties that result from trying to map back the
> content of a FAT image back onto the ISO9660 structure.

xorriso would have to learn to unpack FAT filesystems. But FAT is not
really the topic of xorriso.
Given that the FAT filesystem is freshly composed by grub-mkrescue from a
readily prepared file tree on disk, i deem it more straightforward that
grub-mkrescue simply tells xorriso to put this tree into the ISO.

Either implicitely by having it in iso9660_dir (as patch [2/3] proposes)
or explicitely by a pathspec (like /efi=...temporary.disk.path...).
In the latter case the temporary disk file tree has to survive until the
xorriso run is finished.


Have a nice day :)

Thomas