Originally Posted by wallcraft
The latest BeBook firmware has dropped DRM-ed (encrypted) MOBI support in favour of DRM-ed Adobe ePub/PDF support. The DRM-free MOBI reader in the new firmware acts like the old one, and you still have the option of using the old MOBI firmware anyway. With the new firmware, converting to ePub is also a possibility. This also should have no problems with large files, providing you convert them to ePub using Calibre, because Adobe's reader only processes one "chapter" at a time (and Calibre adds in fake chapters if needed to keep the processed file sizes withing Adobe's limits).
The ADE viewer that's now being released on all the current devices (BeBook, Opus, etc) appears no longer to have the 260k "flow limit" that the old viewer on the Sony had.