Re: Switching debian-installer CD images to GRUB

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

Hi,

John Paul Adrian Glaubitz wrote:
> Looking at the grub-mkrescue.c source, I figured the proper linking would
> be:
>       xorriso_link ("/System/Library/CoreServices/grub.elf",
> "/boot/grub/powerpc-ieee1275/core.elf");

In the end it produces this pathspec

  /System/Library/CoreServices/grub.elf=/boot/grub/powerpc-ieee1275/core.elf

"pathspec" is a mkisofs term. About as old as the Macs with PowerPC.
/System/Library/CoreServices/grub.elf will be the path of the data file
in the ISO. /boot/grub/powerpc-ieee1275/core.elf is the path on hard disk
from which to read the content for the data file in the ISO.

xorriso_link() is kindof a misnamer. It should rather be something like
xorriso_make_pathspec() or xorriso_graft_in().
The variable names in its prototype
  xorriso_link (const char *from, const char *to)
are misleading by "from" becomming the path in the ISO whereas "to" is
the path on the hard disk with the prepared files. (It makes only sense
if time is running backward.)


I wrote:
> > Blessing "p" was not tested yet. You should use some Mac tool to
> > verify that it gets correcty applied by libisofs.

> Isn't the fact that my iBook G4 booted the grub-mkrescue image just
> find proof enough?

The GRUB_INSTALL_PLATFORM_POWERPC_IEEE1275 ISOs don't get blessing at all.
But i assume that they booted in some tests by Vladimir Serbinenko, back
in 2012.
We should not take anything for true before it was tested.


> > An ISO emerges.

> I will give it a try, however with the matching that for the elf files as
> mkrescue uses it. That's what works, after all.

Yeah. For now i refrained from trying to build a ppc64el grub-mkrescue ISO
on an amd64 machine.


Have a nice day :)

Thomas