OT: USB booting the (k)ubuntu Live-CD

[Fabien Meghazi]

> If I accidentally try to boot with the drive connected to my new laptop, it
> starts grub on the USB drive.  It then fails because grub was configured to
> boot off /dev/hda and the partition is on /dev/sdb (or possibly /dev/sdc).  I
> think if I just modified the grub configuration I could get it to boot.  If
> you don't get a better answer today, I'll see if I can give it a try tonight.

Ok I see, but it seems that in this case we have to know what is the root
partition before booting. I wonder if there is a way to have grub dynamically
choose the root partition.

Eg: we have a drive with grub on the mbr and 3 partition on this
drive, let's say
that the system is on the 3rd partition, that would be great if we
could say to grub's
menu.lst to use the 3rd partition of the current device it is running on,
so, by example,  if the bios was asked to boot on usb and it started to
boot using /dev/sdb grub would automatically call the kernel
with root=/dev/sdb3 parameter