I'm feeling lazy, so I'm going to ask a couple of questions I should be able to figure out myself ...
How does it know the book is already on the device? While messing around with tweaking epubs I've ended up with some (but only some) duplicates on my reader -- and I haven't taken the time to figure out why ....
Is it the uuid in the metadata.opf file? (Except that a lot of my books don't have a metadata.opf file
what's up with that?)
If I tweak-epub, modify-epub, or convert, is it still the same book?
What if I copy it to another library?
So now if I clean up books with Modify Epub, and put them on a reading list, they won't be sent on sync - is that correct?
Instead can I view the list, select all, and send to device, to get the same result I had before v1.2.1?