Originally Posted by RWood
The memory space of the 500 is dynamic between the system code and the books/music/photos. This was established at one of the early firmware updates when we had a different user space available after the upgrade. If it takes too much of the main memory we may just have to use the memory stick/SD card reader for book storage.
I don't know how this works, so I'll take your word for it. But I would gladly give up main storage to get ePub capability - I store all my books on an SD card anyway!