The leaflet that ships in the box does not say much. Is there any more in-depth docs available? Ie stuff like reinstall and such. BTW, where is the reset switch? 
Thanks. Had not seen that, yes there is a section about reinstalling. So that is what that SD socket is for
Anything plugged in will be mounted under /media, so it has other uses.
Sure, so the boot loader has code to check for a suitable image there on bootup and upgrade if necessary?