For those who want to know what all the bits and bobs on a cubieboard are, check out the diagrams below, then you too can know which button is the FEL button ;)
T2HHfhXjlaXXXXXXXX_!!329031252 (http://www.flickr.com/photos/sheedl/8658128404/) by sheedl (http://www.flickr.com/people/sheedl/), on Flickr
T2oPW2Xe4bXXXXXXXX_!!329031252 (http://www.flickr.com/photos/sheedl/8657022021/) by sheedl (http://www.flickr.com/people/sheedl/), on Flickr
and where can we find such a layout image of the Cubieboard3 (=Cubietruck) ?
you can download the hardware files from here, you can also find it from download page of cubieboard.org