Dave Graham provided a current version of the Linux implementation on 2010 May 11. The files were downloaded and placed in a directory on a Linux PC. An empty USB-mounted HDD was used and partitions created to match the first two as described in the READ.ME file provided by Dave. This was done using fdisk. The first partition was tagged as bootable.

Then ext3 filesystems were installed on each partition using mkfs.ext3.

The image of the first partition was then copied to the disk:
dd if=dd_sda1 /dev/sdc1

The file boot_sector was copied to the master boot record:
sudo dd if=boot_sector of=/dev/sdc bs=512 count=1

Then the first partition was mounted at /mnt/tmp
sudo mkdir /mnt/tmp
sudo mount /dev/sdc1 /mnt/tmp
Then find out the disk ID:
ls -l /dev/disk/by-id | grep sdc
Then edit the fstab file in the mounted partition so that the / partition has the ID of /dev/sdc1 and /usr2 is at /dev/sdc2, /data at /dev/sdc3. /etc/fstab then looks like this:

/dev/disk/by-id/usb-WDC_WD75_00AACS-00D6B0_DCA425712418-0:0-part1 /                    ext3       acl,user_xattr        1 1
proc                 /proc                proc       defaults              0 0
sysfs                /sys                 sysfs      noauto                0 0
debugfs              /sys/kernel/debug    debugfs    noauto                0 0
usbfs                /proc/bus/usb        usbfs      noauto                0 0
devpts               /dev/pts             devpts     mode=0620,gid=5       0 0
/dev/disk/by-id/usb-WDC_WD75_00AACS-00D6B0_DCA425712418-0:0-part2 /usr2                ext3       acl,user_xattr        1 2
/dev/disk/by-id/usb-WDC_WD75_00AACS-00D6B0_DCA425712418-0:0-part3 /data                ext3       acl,user_xattr        1 2

also edit /mnt/tmp/boot/grub/menu.lst and change the disk ID.

The disk can now be booted from.