Re: "error: invalid magic number" when booting from ISO loopback

[Robert Millan]

On Sat, Oct 31, 2009 at 06:01:56PM +0100, Ron wrote:
> Hi,
> 
> I was playing around with Grub2 (latest svn version) and its loopback
> feature and had some problems to boot an ISO. The ISO file is the 32Bit
> version of Ubuntu 9.10 which is located on a 8GB USB flash drive with
> one FAT32 partition. I've tried to boot it with the following menu
> entry:
> 
> menuentry "Ubuntu" {
>     set isofile="/boot/isos/ubuntu-9.10-desktop-i386.iso"
> 
>     loopback loop $isofile 
>     linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile
> quiet splash noprompt --
>     initrd (loop)/casper/initrd.lz
> }
> 
> This entry fails silently and when the commands were executed one by one
> the linux command shows the error message "error: invalid magic number".

This error means vmlinuz wasn't read correctly.

This could be either a problem in loopback/iso9660 or a problem in the
partition that contains ubuntu-9.10-desktop-i386.iso.

Can you figure out which applies?  For example, if you put a physical CD
with ubuntu-9.10-desktop-i386.iso in the drive and access it from
GRUB (via ata.mod), are you able to load Linux this way?

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."