I ran into an issue with the navigation system on our MDX.  Long story short, the DVD got scratched, and while Navteq was kind enough to replace it, I knew we would be without any maps for a couple weeks.  Fortunately I still had our old map update disc.  Unfortunately, while the navigation system will automatically load the new firmware from a new disc, the system won’t let you re-insert an older disc.

Unless you know how.

I didn’t take screenshots, but this procedure worked and was quite easy to do on our 2008 Acura MDX.  Having read a number of Honda and Acura forums, I suspect it will work on other years and models as well.  I’m posting this because I’ve read a number of people who say you need to take the vehicle to your dealer so that they can reload the firmware, and I’m here to say that, at least in my case, you can do this yourself.

1) Turn the vehicle on.  Remove the new disc and insert the older version

2) Once you receive an “incompatible” error, press Map/Guide + Menu + Cancel for 3-4 seconds to bring up the diagnostic menu

3) Scroll down to Version and click “OK”

4) Scroll down to Download and click “OK”

5) The system will take 3-5 minutes to load the old firmware.  Once complete, your older map disc should load normally.

If you insert a newer disc later, the system will update the firmware with the newer disc again and then you can use the newer maps.