I have a couple non-Nook Android devices with the Nook app installed on them -- a tablet and a phone -- and several epub books that I read and annotated on the tablet. I was surprised, when I copied my epub files over to my phone, to see that highlighting and notes in at least two of those ebooks was carried over.
I can't find anything online about B&N synchronizing annotations for sideloaded ebooks in the cloud; nor can I find any information on how to do it myself. Also, I notice that no new annotations I create on either device get propagated to the other; I wonder if perhaps B&N was actively saving such annotations in the past but no longer is.
My main question is: how can I consistently synchronize annotations between devices in sideloaded books using the Nook app? Secondarily, I'm curious as to how and why some of my annotations were able to be brought across already.