[frostschutz]

The recovery partition has these files: /upgrade/fs.tgz and db.tgz

It will populate the internal system partition, and the user partition with those, respectively.

It should be possible to dope those files to include a fully configured system, so a factory reset would give you the fully prepared reader with your standard selection of books.

However by default, the recovery partition is not very large, so you'd likely have to resize partitions first in order to squeeze more than just a handful of books on it.

You'd have to be familiar with Linux (well enough to resize partitions, and produce/change/modify tar archives with proper paths) to make this work. And you still need access to the internal SD card, as the device will brick if anything goes wrong.

It would be an interesting (albeit dangerous) idea for a mod that automagically takes a snapshot of the current state of the reader, and have that snapshot restored on factory reset.