Ubuntu Upgrade from 9.04 to 10.04 - a CD/DVD way

Something interested is found from the post about the way to upgrade Ubuntu 9.04 subsequently to 9.10 and then to 10.04. The method involves performing Ubuntu upgrade by using an ISO image of Ubuntu 9.10 downloaded from the repository server.

Upgrading Using the Alternate CD/DVD

Download the alternate installation CD via:

$
$ sudo wget http://mirror.aarnet.edu.au/pub/ubuntu/releases/9.10/ubuntu-9.10-alternate-i386.iso

Burn the ISO to a CD and insert it into the CD-ROM drive of the computer to be upgraded.

If the ISO file is on the computer to be upgraded, you could avoid wasting a CD by mounting the ISO as a drive with a command like:

$
$ sudo mount -o loop ~/Desktop/ubuntu-9.10-alternate-i386.iso /media/cdrom0

A dialog will be displayed offering you the opportunity to upgrade using that CD.

Follow the on-screen instructions.
If the upgrade dialog is not displayed for any reason, you may also run the following command using Alt+F2:

$
$ gksu "sh /media/cdrom0/cdromupgrade"

After an upgrade to Ubuntu 9.10 is successfully completed, another wave of upgrade to 10.04 can be done through GUI update manager.

Ref: https://help.ubuntu.com/community/KarmicUpgrades