New install on laptop external drive won't restart

[T J Tulley]

Yesterday I installed Elyssa from iso-burned cd onto partitions 6,7 & 8 of a 200 GB hd in an external case connected to a USB1 socket in my Dell Latitude C840 laptop. Before it would start I had to sudo umount /media/* because it reported that it could not proceed while other partitions were mounted. Installation went very slowly - at the end I accepted the default option to install MBR on hd0. Then came the usual advice to reboot and remove the cd.

When I reboot, I get the message (instantaneously, i.e. no wait, after BIOS boot):
Grub loading stage1.5
Grub loading, please wait . . .
Error 21

I tried Supergrub, but this reported various errors including File not found; when I tried to view partitions it failed to show them but only showed 2 hds. I tried all ways offered to boot, but they all failed.

Today I have tried again - failure - so now I have inserted the USB connection of that external drive into my PC, running Elyssa installed a long time ago from the same cd (and updated and extended!).

The external HD shows its partitions on the screen with no additional action required from me, and the / partition shows /boot/grub/menu.lst where the first active entry is:
title Linux Mint, kernel 2.6.24-16-generic
root (hd1,5)
kernel /boot/vmlinuz-2.6.24-16-generic root=/dev/sdb6 ro quiet splash
initrd /boot/initrd.img-2.6.24-16-generic

Clearly the partitions are numbered from 0 here, it appeared in the installation partitioner as Partition 6.
More puzzling is the identification of the drive: the screen showing it is headed:
disk-2 - File Browser.
The 'disks' in the laptop shown in the installation partitioner were hd0 (internal hdd), hd1(cd-rw), and hd2 (external hdd). The installation was to hd2, which appears to correspond with the header of the screen, "disk-2 - File Browser".

But: /boot/grub/device.map in the external drive / partition shows:
(hd0) /dev/sda
(hd1) /dev/sdb
whereas in the installation in this PC, the corresponding file in its / partition shows:
(hd0) /dev/sdb
(hd1) /dev/sdc
(hd2) /dev/sdd
and I wish it had installed starting with sda!

Could the failure to boot be related to an incorrect drive identification in menu.lst?
I shall be most grateful for advice, which I will await.

[VVV]

try a mobo bios upgrade
just remember if the upgrade fails yolur computer will not work

[T J Tulley]

Thanks VVV - I installed the latest Dell BIOS for my laptop quite recently - it was dated 2005.

The BIOS doesn't specifically recognise USB drives for boot sequence, but I enabled the next possibility after floppy, CD, hd0.

In any case, the MBR is on hd0 as I said.