Comment 40 for bug 120375

I have run into the same problem where my disk upgrade path included booting from temprorarily degraded array.

I have tried to update /etc/mdadm/mdadm.conf with the new file system UUIDs
(using mdadm --detail --scan and replacing the corresponding line in /etc/mdadm/mdadm.conf)
and after that update-initrd

Now the system seems to be booting without any problems.

I have also used -e 0.90 paramater in mdadm when assembling the degraded array (to create an older version of superblock that is recognized by the kernel), though I am not sure whether this had anything to do with the outcome.