“The Open Book is my long-standing attempt to design a comprehensible and accessible e-book reader that you can build yourself (or at least have manufactured affordably). The current edition is something I’m calling the “Abridged” or “Developer Preview” edition. It’s designed to be incredibly simple: there are 7 through-hole and 14 surface mount components, nearly all in a chunky 1206 package that’s easy to hand solder. The tradeoff is that it has no LiPo charging circuit; instead it uses AAA batteries, making it a bit more chunky than previous versions of the book.
The goal with this version is to get hardware in hands so we can start hacking on firmware.”
I’m sure that the eventual plan is to support ePub.
I’m not sure it will ever get there, because it’s not a well resourced project, but I personally don’t like criticizing one person’s efforts, which they are making freely available.