greatone76 has the procedure exactly correct. There have been a few card "downloads" posted in this thread. But, unfortunately, those don't include all the data on the card. I think there a few more bytes of information that weren't included in those listings. Toward the end of the memory on the card, I think there are specific values that are returned to the microcontroller after successfully sending the correct password. I could be wrong, though.... Also, I'm not sure if the UID bytes at the start of the data can be overwritten.
As soon as my NFC shield arrives, I'm going to give this a try. It was supposed to be here on Monday. Still waiting... I have the original spool with a few meters left on the card. And, I have two new spools (one black, one natural) I was going to try reading and cloning. I've already sniffed the password for the original spool just like was done earlier in this thread.
If this works, I would imagine for those who didn't want to deal with purchasing a logic analyzer, a "pre-programmed" 100m card could be swapped along with the appropriate password. Then, all you'd need is the password/data from the card in an Arduino to reset the length periodically.
Also, I know there was talk about the potential of temperature differences in XYZ PLA vs. others being a problem. I've been using Hatchbox PLA (advertised 180-210degC) without modifying the output/G-code of the XYZ application. The prints look just as good as the original PLA included with the printer. No jams or other problems. I'm sure there are other PLAs that will work (and some that won't), too. Just thought I'd pass this info along in case someone else is getting started and looking for a substitute PLA to use. There is one drawback, though. The XYZ spools are smaller in diameter (probably because there's less PLA). I had to open up the side of the printer, disassemble the existing spool holder (and NFC-related stuff) and make a spool holder out of spare plastic plumbing pieces to get it to feed halfway decent.
