I had a 40 gig internal IDE harddrive that was fully configured with Fedora Core 2. However, I took that harddrive out and converted it into a external usb 2.0 device.

I installed a fresh 160gig IDE harddrive and it has windows xp on it.

I want to be able to boot into linux if i tell my bios to boot from USB HDD, this works up to the point of the Grub bootloader, but when i select my linux kernel i get a kernal panic... maybe the USB HD is still pointing to itself as it it were an internal IDE?

here's the error i get after i select the kernel from GRUB:

Uncompressing Linux... Ok, booing the kernel.
audit(1095540111.742:0): initialized
Red Hat nash version 3.5.22 starting
mkrootdev: label / not found
mount: error 2 mounting ext3
pivotroot: pivot_root(/sysroot, /sysroot/intrd) failed: 2
umount /initrd/proc failed: 2
Kernel panic: No init found. Try passing init= option to kernel



and here's the config i have for grub:

root(hd0,0)
kernel /vmlinuz-2.6.8.1 ro root=LABEL=/ rhgb quiet
initrd /initrd-2.6.8.1.img


any ideas? thanks.

I have done some reading on the net and found the following information.

http://www.simonf.com/usb/

once you figure out a nice initrd image, it is likely you will also need to amend your grub.

Grub detects normally from IDE to external so your usb will become
(hd1) and its boot partition becomes (hd1,0)

2) it is likely you may want to put /boot after kernel like this
kernel /boot/vmlinuz etc

3) it is also likely you need to amend your kernel line now you have an usb rather than ide so this fragment could be

kernel /boot/vmlinuz root=/dev/sda1 ro sda=ide-scsi

4) Being lazy I would recommend you use a knoppix or sysresccd (rescue cd) to see what it AUTODETECTS you may need to write stuff down at boot or go into the file /etc/fstab then match your grub stuff.

5) Use the option at mbr boot with grub to press E to edit your current boot lines to amend the root and the kernel etc

roughly try

root (hd1,0)
kernel /boot/vmlinuz root=/dev/sda1 ro sda=ide-scsi
initrd /initrd.img (or initrd.gz).......remember you have to create this one.

6) This edit is only temporary so no save occurs of the right option so you could try the above with out the initrd line and see what happens??