I was also looking at this as well and also at the SD specification and info from gpsunderground and other forums, etc and here's the summary of all the info so far:
- The free and donwloadable VW/Skoda update 036 is binary identical to the 036 version which is shipped with the latest Leons.
- If you put this update 036 on the original SEAT navigation SD-card that came with your car (and if the SD card is older version, for example 034), the update won't work => obviously the protection is on the SD card
- If you use another SD card and backup your working navigation content to it, it won't work => again, the protection is linked to the SD card
- If you format your original SD card and then restore your backed up content, it will work => so, the protection is not in the visible partition of the SD card but is rather on a hidden partition
- Reading the SD specification, we see there is so called "Protected Area" which is part of the SD card that is not accessible through the normal filesystem operations and its content is (mostly) read-only and created by the manufacturers of the SD-cards
- The protected area contains, among other data, the so called CID which is a 128-bit data identifying the manufacturer of the content, an ID of the content, etc.
- Certain manufacturers of GPS software, such as Garmin, use the CID to lock the content to that particular SD-card. You can copy the content to another SD-card, however when the GPS hardware reads the content, it will also read the CID and will expect it to match certain values
- There are however certain manufacturers of SD-cards who sell SD cards with CID that is user writable (which seems to be some kind of violation and probably illegal). I haven't yet discovered brands/models and I suspect those are some Chinese unknown brands. That needs to be researched. I guess eBay would be a good place to look for such.
- Even if you find such SD-cards, it seems there's not much information and available software to write the CID, however there are some partial successes with that, see the links I will post.
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So, there are multiple approaches:
1. Since VW and Skoda allow using the free updates, their units are probably not checking the SD-card validity. Maybe we can use VCDS to make SEAT units allow navigation content on any SD-card.
2. By using SD-cards that allow CID writing, we may be able to program the CID to match the one expected by the unit. Reading CID is possible with some software on the Internet, however it requires SD-card reader connected to the PCI bus of the computer and not USB one. Most built-in laptop/desktop card-readers are PCI. Writing the CID is another challenge though.
3. Using some SD-card adapter which is hooked to some intermediate hardware unit (faking the CID on CID-read command) and then just relaying all the signals to a regular SD card can trick the unit into thinking the original SD-card is inserted. This is a rather nerdy approach and I am not sure if there are guys here who are that good with such stuff
And here some links:
http://www.digitalspirit.org/file/index.php/obj-download/docs/sd/TOSHIBA_SD_Card_Specification.pdf
http://gpsunderground.com/forum/general-information/6929-why-copied-sd-card-not-working-your-device.html
Some success with writeCID