I've got a 2011 C Class with Comand Online and I've only got an ipod cable and I am missing the other two. I am trying to get the unit to read a 500gb hard drive but it doesn't appear when plugged into the basic USB socket although USB sticks play fine from there. Do I need to buy the Media interface/USB cable so I can plug into the other socket, the one that takes the ipod lead or is a 500gb drive beyond its capabilities? From what I gather there have been three versions of NTG4.5, the earliest, mine, with no choice of colour scheme just papyrus. Version 2 with a Silver/Red colour scheme option and version 3 with different hardware but better internet connectivity. Is an upgrade from v1 to v2 available?