Fedora Users — Usb Hard Drive Boot.

With my motherboard, I just leave the USB drive plugged, and change a bios setting to boot from the usb port. (Intel Motherboard D945gnt).

Leslie Satenstein

Message: 14
Date: Tue, 01 Jan 2008 13:12:54 +0000
From: John Austin
Subject: Re: F8 installation in external usb disk (not USB key)
To: For users of Fedora
Message-ID: <1199193174.5598.76.camel@fuerte>
Content-Type: text/plain

On Mon, 2007-12-31 at 12:33 -0600, Mikkel L. Ellertson wrote:
> John Austin wrote:
> >
> > The only real decisions are to do with how to boot.
> >
> > If the USB disk is to rely on the MBR of a main SATA/IDE type disk then
> > choose the /dev/sdxy device associated with the USB disk at install
> > time.
> > Then add an entry to grub.conf on the fixed disk.
> > title USB disk
> > root (hdp,q)
> > chainloader +1
> >
> > In addition after install I would then configure grub on the MBR of the
> > USB disk as well such that I can boot the disk with and without the
> > presence of the "main", "fixed" disk.
> >
> What I did was install a copy of Grub to the MBR of the USB drive,
> and then create an entry like this in the SATA Grub menu:
>
> title USB disk
> root (hd0)
> map (hd0) (hd1)
> map (hd1) (hd0)
> chainload +1
>
> Because of the map commands, the USB drive is hd0 when the chainload
> command is executed, and it loads Grub from the USB drive. (hd0 is
> the entire disk, starting from the MBR.) From there it is the same
> as if you had used the BIOS option to boot from the USB drive. The
> only thing you have to be careful of is if you have more then one
> USB drive plugged in. You will get a Grub error is the wrong one is
> detected first, and does not have a boot loader on it.
>
> Mikkel
> --
Hi Mikkel

I liked your way of doing things but when I try on my machine as soon as
I use the map command grub gets in a real muddle.
It is not a problem to me but it should work !!!!!!!!!

Even simple things from the grub command start failing

Eg
I can boot into interactive grub from SATA disk
and re enter grub many times as follows

With SATA=(hd0) USB=(hd1)
(SATA is F8 x86-64, USB is F8 i386) both updated to within 3 days.
Both have /dev/sdx1 = /boot, /dev/sdx2 = /, /dev/sdx3 = swap

root (hd0)
chainloader +1
re-enters the SATA grub menu

root (hd1)
chainloader +1
enters the USB grub menu

root (hd1)
chainloader +1
re-enters the USB grub menu

root (hd0)
chainloader +1
re-enters the SATA grub menu

as soon as I do the following grub falls apart !!!!!!!!!!
root (hd0)
map (hd0) (hd1)
map (hd1) (hd0)
chainloader +1

Interesting ?

John