Be careful. I have tried to update mine. And I've tried copying mine for others. Nothing seems to work at the moment other than a genuine one which is very expensive, if it's actually obtainable.
If you try one and it doesn't work, the touch screen freezes and you can't get to the button that opens the front to get the dud disc out!!
I've been looking at the Aisin Warner discs that Toyota and Lexus use, but I haven't found one to try yet. Look at the AW part number on the disc. The Lexus/Toyota ones are very similar. It's tempting, but still around £120 a disc.