I have been fiddling with the upgrade from a 3.0 SW version to 3.4. My experience so far was mixed, since the first USB stick I made with the full 3.4 packages (with EU maps) failed 80% through and the unit didn’t recognize any USB after that. I had to leave the car overnight and it successfully reflashed a 3.4 package without any maps in it (in the interest of time and being worried that the long process is affecting my UBS stability).
I now have a 3.4 installed but without any maps and I get a “nav malfunction” error.
My plan is to create via the tool a “Downgrade” package to install the maps back on the unit.
Not the tricky part comes, is it possible, if anyone experienced with this, for example, to only install the maps without any voice nav files (as far as I can see those have ~8GB). I wouldn’t really need the voice cues and would appreciate if the system had fewer files to copy so I don’t risk the full 80 minutes of install that could fail again.