Mazda lists part number of the navigation SD card as 0000-8F-Z09A. However there are many cards on sale on eBay with part numbers BHP1-66-EZ1A / BHP1-66-EZ1B / BHP1-66-EZ1C / BHP1-66-EZ1D. What's the difference?

 

Not being a parts guy, I'll take a guess that the first number is Mazda catalog for particular country/area. Typically, as the part is improved, redesigned or updated, the same number will end in a letter. i.e. A, B, C, etc. So the SD cards you see with the suffix A, are older than the ones with suffix D. As the years move forward, we'll see E, F, and who know where it will end. As long as the SD card is labeled with your model, shouldn't be a concern. I don't have a navi unit myself, but from what I've been reading, doesn't TomTom have the updates online? Seems that would be easier than an Ebay buy.

Mazda does have a fix if you have an older unit with freeze and location issues.

 

Talking with a Mazda person who is much more informed on the Navi systems than I, The SD card acclimates itself to the vehicle and inhales the VIN. Short answer, a SD card from a different Navi system may not work in your vehicle since it married the vehicle it was activated in. Buy replacement from dealer.