Originally Posted by davidfor
What do you want to back up?
For the Kobo books, do a sync with the desktop app or over Wifi. This will also sync bookmarks and annotations. After the reset and a sync, they will come back.
If you used ADE to put any DRM'd books on, they should still be in the ADE directory, so I don't think you need to anything.
For the other books, if they are already in calibre, there isn't anything to do, except remember what is on the device. If they aren't in calibre, just attach the device and copy them off using Explorer.