Hi everyone,
I hope a Mifare Classic expert sees this post. Here is the problem: I have bought Mifare Classic 1k tags (blank) and I am able to read them using the Android App "NXP TagInfo" (full scan shows the exact memory content). The tags are blank with default passwords (FF..) for A and B. "NXP TagWriter" supports NDEF-formatting Mifare Classic tags but ONLY if they were manufactured by NXP (mine aren't which is why this is not working). So I need to find a way to NDEF-format my tags, otherwise they are useless to me. The android app "MIFARE Classic Tool" allows me to dump the memory, change a few bytes and write the dump back to the card. So what I need is code that does this for me (I have an ACR122U so it does not have to be Android specific code). I already skimmed over the three NXP documents that specific Mifare Classic Tags (AN1304.pdf, AN1305.pdf and MF1S503x.pdf), but they are too complex. I would play around and try stuff but the documents explicitely say that invalid writes might leave certain areas of my tags in a read-only state (which I do not want to risk). Here is the memory dump of my empty tag, is anyone here able to tell me which bytes need to be changed to make it NDEF-formatted? Dump of bytes: https://pastebin.com/uhqH3URX-----
So my understanding about the dump is:
Key A = Key B = (FF FF FF FF FF FF)
Access Bits = FF 07 80 69
In total there are 16 Sectors with 4 blocks per sector and 16 bytes per block.
This tag supports ISO/IEC 14443-3 (Type A) and is NdefFormatable in theory but currently empty.
So again: Which bytes do I change to format every empty block as NDEF?