So it looks like I'll have to buy an extra SD card.
One for the mobi-firmware, the other for the ePub one. I can de_DRM and convert all my mobi-books but then I'll loose my dictionary.
So it'll be normaly mobi and only ePub when there is no mobi available (eg the books by Joe Abbercrombie).
OK I can live with that. When the new firmware is (rather) bug-free than I'm a happy puppy
