Below is my successful experience in updating Mazda SD card. You DO NOT need to format the card as to what the software asks you to do. DO NOT FORMAT IT or else you will lose your data!
1. Download the latest TomTom HOME (Not MyTomTom). My current version is 2.9 (as of July 2012).
Downloading site:
http://www.tomtom.com/services/service.php?id=16&tab=87
(you may have to select your country, close the window, and then come back here to click the same link again)
2. You have to launch TomTom HOME software first before inserting SD card. Otherwise error message will appear if you insert card first and then launching software (which is how this card is programmed to do and it doesn't work that way). I use Mac and it sees the SD card with no issue by doing it my way. The same goes with Windows user.
3. Create a new account that associates with this SD card. The software should automatically detects that it's a "Mazda Navigation System NB1" SD card.
4. Download the latest update which is actually will be saved in your computer hard drive, not on the SD card yet.
5. After finishing download, your TomTom HOME software will unknowingly disconnect your SD card. Don't panic. Just re-inserting the card back. It will ask you to re-download the same update again. Just ignore it.
6. Go to "More" > "Manage Mazda Navigation System NB1". Click on "Install Items from computer" tab. Then click "Add" button which will physically copying files into your SD card.
7. Take the card out and plug into your Mazda CX-5. Then start your engine. First thing you see is your Mazda is copying files into the system from your SD card. Then the next screen you will see system update progress bar. There's also a graphic indicating not to remove the card while updating. When it's done, your Navigation will shut down and disappear but your XM radio will still be running independently. DO NOT PANIC.
8. Shut down your car engine and restart your car. This is how you physically reboot your Mazda Navigation System (pressing OFF button on your system will not work). Your car is a giant chunk of PC. True story: One day my Mazda Navigation System crashed and froze while I was driving. I had to stop at an emergency lane and shut off my engine completely and then restarted the engine. Then my Mazda Navigation System was back on and working normally again.
9. After rebooting your computer (Mazda CX-5), your Mazda Navigator System is back on and working again. You are done!
