Actually, this one should be easy as I assume you're looking for Canada & Alaska and there is only one map that can be activated so:
1. Backup your current setup to a safe place
2. Download Canada Alaska 995.8549 = 181MB from
[Please Register or Login to download file] (PW: navitotal)
3. Once downloaded, delete your old map from your device and replace it with the new map you've downloaded & extracted
4. Now to activate....download FastActivate from
here and extract it to the root of your device.
5. Run FastActivate from that location and select options 2 & 3 (waiting for successful messages each time)
6. Done.