Updates...
Tried to connect the gps to a notebook using a USB cable. Installed USB Garmin drivers.
The gps screen shows a page with two big buttons: Garmin Mode and USB Disk Mode
Using Garmin Mode the gps is recognized as NAVI with the correct unit id number. I was unable to read the internal memory.
Using USB Disk Mode i was able to read the sd content as external disk.

If you press the reset button a white page on the gps screen appears, showing lot of data in two column. (like temperature=34 °, Voices=3 etc, etc.) In this page it seems waiting for something... maybe a pre boot mode?

This gps allows reading map images of 4 GB instead the 2 GB limit of 2006-2008 models.

Hope this helps, but i don't see a big interest in this thread.
No Goldwing owner interested in updating maps and fw in all the world? I can't belive it!