Just download and unzip them. Put them on USB stick not in any folders... I just brought a cheap small capacity one for updates...
Press MENU on headunit, Tap SETUP, Tap SOFTWARE, it should find the updates on the USB stick...
Bit weird but the system firmware on my DNX525DAB is newer than whats available for download?! (Version 1.7.0)
Can't fault the unit,only cost £699 brand new from a SEAT dealership on ebay, just a few small niggles one being still no DAB radio artwork, does anyone know how to get it to display? I've done a Google search and other owners on other VW Forums can't get it to display either, just a picture of a radio mast with "No Photo" text?