One of the first things I tried to do was to move the 277 books under /pocketbook/books to an 8gb Sandsik SD card. I wanted to do this as there was only 12mb left on the internal memory! (it's hard to see how and where your space is used up, the file manager is very rudimentary.)
Unfortunately, when I try to move the files it just says 'cannot move file'. This doesn't bode very well for backing anything up to SD card! (I've downloaded several programmes and books through the PB to this card, such as Aldiko and the card works fine).
I plan to use a second 'new' card for the update, but at this rate it isn't going to be possible anyway. 1. the PB won't connect to Mac, 2. I can't back up files to the SD card.