The eDGe doesn't support SDXC cards as far as I know. I'm also not sure what happens if the SD card is removed if it has the Library on it (you can email techsupport@entourageedge.com to ask, though). Adding an SD card probably will have limited benefit for the capacity of applications, as their data storage usage is trivial compared to a library of ebooks, or a collection of MP3's and videos.