[taming]

It makes sense that the sideloaded books would not have access. It was a huge change in the way the Db works. I'd be tempted to do a factory reset or remove the books from the file system before doing the update and just deal with having to reload the books.

When you update from an SD card it replaces the entire kaboodle. Nothing, nada, zilch left on the device from the old setup. When I did update after update in beta, I decided that some of my books that had been in main memory (actually most of them) could very nicely live on an sd card.

Try to reframe it as a chance to do a big housecleaning!