Try different approach to onboarding / updating
Add a script which will clone (or pull) the repos and then (forcibly) create a single file (outside of onboarding -- probably in the clone root serpent-os/ dir) whose one purpose is to pull onboarding and then rerun the (possibly updated) clone/pull+build script.
Motivation:
Without pulling onboarding updates, the process breaks any time a new repo is added.