Far as I know, the CID of the SD card can not change because is in a prom, memory that is only write once.
But I found this post where people is talking about SDs that it can rewrite because are manufactured with eprom.
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Knowing the CID of the original SD, and buying this kind of SD we can make a perfect clone.
Another way, would be change the CID number in the garmin software, this number should be on the *.unl or *.gma files. But the problem is that the information is encrypted.
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