Re: Booting from USB HDD without BIOS support

From: Bruno Taglienti (bruno.taglienti_at_roma1.infn.it)
Date: 06/15/05


Date: Wed, 15 Jun 2005 12:59:48 +0200

Stephan Keil wrote:
> Hi all,
>
> I have an external USB harddisk and installed Linux (SUSE 9.3) on it.
> Unfortunately my BIOS does not support direct booting from USB harddisks.
> I suppose it is possible to setup e.g. a small boot CD (booting from CD
> is supported), which loads a USB driver and finally boots Linux from the
> USB harddisk.
> Can anyone please give me some hints how to do this? Or does anyone have
> a better idea how to boot from the harddisk?
>
> Thanks and Best Regards, Stephan
>
> P.S.: Background: My system is a Medion MD8383XL with Phoenix 6.0 BIOS.
> The main harddisk is a SATA device, which is full of <shame> Windows XP
> </shame>.

What you need is to boot from CD with an initial ramdisk including
the usb-storage support (mkinitrd --with=uhci-hcd --with=ohci-hcd
--with=ehci-hcd --with=usb-storage)
The initial ramdisk including the usb-storage is crucial to be able to
mount the root fs on the USB drive.

Then Google search for "grub on CD" to learn how to make a grub-bootable
cd-rom.

The typical grub.conf entry should be as follows:

title USB boot
         root(cd)
         kernel /vmlinuz-2.6.X-Y root=/dev/sdaZ
         initrd /ramdisk-2.6.X.Y.img

I made all that in practice and it works.