How to upgrade Ubuntu without their upgrade tool

The problem

The heart of the problem is that sometimes when you try to upgrade ubuntu the upgrade fails. This happened to me when trying to upgrade to plucky (25.04). The tool would just fail and I tried to waiting it out hoping that ubuntu will solve the bug. No such luck. Finally I decided to upgrade it myself manually and it worked like a charm.

The solution

Sync up

The first thing you need to do is sync up with the previous release:

$ sudo apt update
$ sudo apt dist-upgrade

Disable third party repos

The next thing is to manially disable any non ubuntu source of packages from /etc/apt/sources.list.d. I usually just create a folder called /etc/apt/sources.list.moved and move all but ubuntu there.

Setup the ubuntu source to the new distribution

update /etc/apt/sources.list.d/ubuntu.sources to the following content (replace your distro name):

Enabled: yes
Types: deb
URIs: http://us.archive.ubuntu.com/ubuntu
Suites: plucky plucky-updates plucky-security plucky-backports
Components: main restricted universe multiverse
Architectures: amd64
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

Upgrade and solve all issues

$ sudo apt update
$ sudo apt dist-upgrade

You will need to solve issues along the way but they are standard things.

Reboot

And that's it.