[Grml] grub2 loopback feature

Alexander 'Leo' Bergolth leo at strike.wu.ac.at
Tue Jun 15 17:38:59 CEST 2010


I'd like to use the loopback feature of grub2 to boot a grml iso-image
that resides on a USB drive.

Is there a way to make grub jump to the existing /boot/grub/grub.cfg in
the ISO and show its contents as a submenu?

I am thinking about something like:

/boot/grub/grub.cfg on USB drive:
-------------------- 8< --------------------
menuentry 'GRML' {
  export iso_path
  export bootid

  loopback loop $iso_path
  set root=(loop)
  configfile /boot/grub/grub.cfg
-------------------- 8< --------------------

Unfortunately, when selecting the menuantry above, my box reboots.

When trying the same on the grub commandline, it reboots at
"set root=(loop)". So root=loop doesn't seem to be supported...

On the other hand, "configfile (loop)/boot/grub/grub.cfg" perfectly
jumps to grmls boot menu. But when using this approach, I guess some
support in grml's grub.cfg would be needed so that grub can correctly
locate the image files.
(Maybe a $loop variable prepended to all filenames in grmls grub.cfg,
which is conditionally set to "(loop)"?)

Any other hints?

e-mail   ::: Leo.Bergolth (at) wu.ac.at
fax      ::: +43-1-31336-906050
location ::: IT-Services | Vienna University of Economics | Austria

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