Updating MMI basic

A friend has bought a 2006 A6 and has emailed me to ask if I know how to update the MMI Basic satnav. I don't know much about satnav units so thought it best to ask here. Can updated be downloaded legitimitely or via bittorrent sites etc?
Where did you find the navigation update mate? I think now that the MMI basic is the RNS-D unit. I don't know if there is any way to update it though. Most people seem to pay a lot of money to upgrade to the RNS-E instead.
that link doesn't work mate.

I thought MMI basic was RNS-D but don't know what MMI high is. RNS-E perhaps?