Ubuntu USB stick install, part 2

I finally got a successful install. But it took several attempts and a lot of Google.

First attempt

In the fit-PC BIOS setup, I set Drive C: Nand Flash but neglected to set Drive D: IDE. So when the installer got round to the partitioning stage it could only see the USB stick, not the hard disk. Hit reset button and start again...

Second attempt

I didn't create a separate ext3 /boot partition, just XFS root and /home partitions. Apparently installing GRUB on an XFS partition is not a good thing. Near the end of the install, the installer offers to install LILO for me. Now I dimly remembered going through LILO versus GRUB before and preferring GRUB, so I try to install GRUB anyway. The installer warns me that this is a bad idea. When I ignore that this makes a fatal error in the install which then hangs. Grit teeth, hit reset button and start again...

Third and fourth attempts

I created a separate ext3 /boot partition to stay sweet with GRUB. So I now have

#1 primary 100MB ext3 /boot
#1 primary   4GB XFS  /
#5 logical 246GB XFS  /home

Now the install completed successfully each time. But it all ended in tears when I tried to reboot the fit-PC. Each time, it immediately dropped to a debugger interface, saying Embedded BIOS Debugger Breakpoint Trap and refused to do anything else. Weep, hit the sack and try again in the morning...

I noticed that after each install attempt, I could no longer boot from the USB stick. It gave GRUB Error 21. I could fix the stick by reconnecting it to my old Linux box and doing install-mbr /dev/sdb. But why?

I finally guessed that the Ubuntu installer must be installing GRUB to the MBR of my USB stick, instead of the hard disk in my fit-PC where I needed it. Armed with that hunch, Google finally gave me some answers, like this, this and this.

Fifth attempt

I let the Ubuntu installer run to the very end, where it tells you to reboot. At that point, I opened a console and took a look around.

I found (fdisk) that my hard disk partitions were mounted on /target. So I did

# chroot /target
# grub-install /dev/sdb

to install GRUB into the MBR of the hard disk. Then I went back to the installer's console and let it finish.

On restart I removed the USB stick, hit DEL to enter the BIOS setup, reverted to Drive C: IDE and saved to reboot.

On first attempt GRUB started (phew) but said

Error 21: Selected disk does not exist
Press any key to continue...

So I did. Then GRUB gives the menu list of image it can boot and allows you to edit and boot them. I edited the entry for the first image. It's first line was root (hd1,0). I edited that to root (hd0,0) and the hit 'b' to boot. The system booted at last.

Once in, I took a look at /boot/grub/menu.list. All three had root (hd1,0).

I rebooted to confirm that GRUB would fail again with same error.
It did. I fixed as before. Once back in, I edited /boot/grub/menu.list to change all the hd1 to hd0 and rebooted again.

At last, the system boots successfully. Now I can get on with the more interesting stuff.