Re: How to prepare an ISO 9660 CD for booting via GRUB ?

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

> I attach the patch I used for dirty checks

Oh. You already tested.
And ? Did it boot ?


> > Just yesterday i moved that setting from option
> > -b to option -boot-info-table,
> Thanks.

Even better: i now tested that omitting
-boot-info-table really prevents the patcher
function.


> Why not to determine it [-boot-load-size] from
> file size by default?

Because mkisofs doesn't do that, afaik.
One never knows what happens if one deviates from
the old ways by default.
(See Joliet and grub 1.96. I now go the old
way by default. So grub-mkrescue 1.96 boots from
CD.)


> The problem is that I would like to have efi+bios cd with 2 eltorito
> entries: one with platformid=0 and another one with platformid=0xef.

Ahum. More than one boot table entry.
Would they point to different boot images ?

I.e would we have
  -b <BIOS-image> [-boot-info-table] --efi-boot <EFI-image>


Is it possible to get an exact prescription, what
info to write at which byte in the boot catalog ?

I have a PDF: El Torito 1.0, January 25, 1995.
Figure 1, "Multiple Boot-Image Configuration"
seems to be what you intend.
I will try to match this with the existing code
in libisofs (by Vreixo Formoso).


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> > Do i get it right that you want the LBA [...]
> > to be as low as possible ?
> Yes and also the offset to files from boot/grub
> and metadata to reach it

I learned meanwhile that there is a feature
"weight" in libisofs by which one can influence
the sequence of the data LBAs. An IsoNode with
high weight will get a low LBA.

So this is merely a matter of suitable options
in xorriso, by which one can put weight on files.


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Have a nice day :)

Thomas