Yeah finally fixed an annoying issue with my Linux Server at home (nice to flex my Linux admin skills!) documenting it here in case I ever need the commands again or its useful to others:

Problem:

Ubuntu 9.04 no longer booted after a minor update (from .15 to .16) with my Software RAID setup as described in these reported bugs:

https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/330298

https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/158918

Fix:

Following the instructions on https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/136252/comments/5 fixed the problem but you need to run update-initfs -u so it updates.

Amazing what you learn when having to fix this kind of stuff – for one I now understand the memory based file system that linux uses during boot better.