Upgrade from 5.2 to 5.4

Please, describe the problem here and provide additional information below (if applicable) …
We are running ruby script as pre-upgrade step from 5.2 to 5.4. There are few machines that error out with “Cannot find unmanaged disk inside template” message. Simply they have disks that were added through vcenter and nebula. What is the best work around for those ?

No ideas anyone ?

My work around was to add unmanaged disks to few templates and run through upgrade.