@Neil
Since using latest firmware is "highly recommended", now that I have modding tool to activate features on my Nuvi 3490, I upgraded from 6.30 (under which I activated MP3 and Video Playback using 0 bytes xml files) back to 8.20. I expected to loose MP3 and Video Playback. To my amuzement those features did not get deactivated. Evidently, later software blocks feature activation via 0 bytes xml files, but once a feature is activated it does not deactivate it.

Quote Originally Posted by Neil View Post
Drag the gcd file onto the WebUpdater icon with your nuvi connected, it will load it to the unit and the traffic receiver should be automatically updated when you connect it to the unit later.
Not so lucky here. I dragged firmware update for type 3 traffic receiver gcd file over Webupdater icon. That launched Webupdater and it said "Device updated", but did not offer me to update to type 3 traffic receiver. What it did offer were supplemental updates pertaining primarily to voice. Also it copied that type 3 traffic receiver gcd file to .System folder and renamed it GUPDATE.GCD (MD5 for both files is the same value). After I connected the unit to the traffic receiver Traffic receiver Status still says GTM60 Software Version 2, Class 2.