USB stick update: Debian is back, plus GRML

In the previous post on the multi-boot usb stick, Debian had to be dropped, due to missing support of iso-loading in the Debian installer iso images. Thanks to helpful comments from Jonathan McDowell and private emails, we found a way around this. In addition to having again an installable Debian image, I also added GRML support.

There are a few tricks necessary to get this going, though. Let us start with the easy part, grml:

Grml

Quoting from the home page of Grml

Grml provides an excellent selection of software packages for installation, deployment and system rescue. You’ll get sysadmin’s favourite tools. Choose between a x86 and an amd64 version depending on your needs or just grab the multiboot ISO grml96, providing 64bit and 32bit ISOs in one single place.

I went for the 64bit version Version 2014.11 (named “Gschistigschasti”, a typical Austrian expression for ‘fuss’), as most computers nowadays are anyway 64bit capable, downloaded the image file grml64-full_2014.11.iso, and saved it into my USB stick’s boot/iso/ directory, where there are already the other iso images.

Then, with the help of the Grml web page which provides guidance how to boot from ISO, I added the following entry to my grub.cfg:

submenu "GRML 2014.11 ---> " {
  menuentry "Grml Rescue System 64bit" {
        iso_path="/boot/iso/grml64-full_2014.11.iso"
        export iso_path
        loopback loop (hd0,1)$iso_path
        set root=(loop)
        kernelopts=" ssh=SOME_PASSWORD_HERE toram  "
        export kernelopts
        configfile /boot/grub/loopback.cfg
  } 
}

Note that if you add the ssh=SOME_PASSWORD_HERE part, an ssh server is started and the root login password will be set to SOME_PASSWORD_HERE, so choose it wisely (and different from your normal passwords!). If you don’t want a running ssh server, simply remove the ssh parameter.

That’s it, booting into Grml takes quite some time, but worked out nicely.

Debian Jessie installation

As mentioned in the previous post, booting Debian/Jessie installation images via any method didn’t work, since the iso images is never found. It turned out that the current installer iso images do not contain the iso-scan package, which is responsible for searching and loading of iso images.

But with a small trick one can overcome this: One needs to replace the initrd that is on the ISO image with one that contains the iso-scan package. And we do not need to create these initrd by ourselves, but simply use the ones from hd-media type installer. I downloaded the following four gzipped initrds from one of the Debian mirrors: i386/initrd text mode, i386/initrd gui mode, amd64/initrd text mode, amd64/initrd gui mode, and put them into the USB stick’s boot/debian/install.386, boot/debian/install.386/gtk, boot/debian/install.amd, boot/debian/install.amd/gtk, respectively. Finally, I added entries similar to this one (rest see the grub.cfg file):

submenu "Debian 8.0 Jessie NetInstall ---> " {
    set isofile="/boot/iso/firmware-8.0.0-amd64-i386-netinst.iso"
    menuentry '64 bit Install' {
        set background_color=black
        loopback loop (hd0,1)$isofile
        linux    (loop)/install.amd/vmlinuz iso-scan/ask_second_pass=true iso-scan/filename=$isofile vga=788 -- quiet 
        initrd   /boot/debian/install.amd/initrd.gz
    }
    ...
}

Again an important point, don’t forget the two kernel command line options: iso-scan/ask_second_pass=true iso-scan/filename=$isofile, otherwise you probably will have to make the installer scan all disks and drives completely, which might take ages.

With that in place, the stick now is back to full working, plus an added Grml. Thanks everyone for the suggestions.