Recently I have bought some Chinese magic cards which are supposedly block 0 writable. I am able to write all of the blocks except block 0. I have done some research and figured out that you need to send some SPI commands to the RC522 reader to enable the backdoor.

If writing block 0 does not work, you probably have a backdoored card: To enable the backdoor, you need to send the following sequence to the card: (everything in hexadecimal)

1. RC522 > Card: 50 00 57 cd (HLTA + CRC)
2. RC522 > Card: 40 (7 bits only)
3. Card > RC522: A (4 bits only)
4. RC522 > Card: 43
5. Card > RC522: A (4 bits only)

The problem is I can not figure out how to do it. I have stumbled on a library for Arduino which has this feature but I am using Raspberry pi Pico w with this library.

Is there an existing python library or maybe some example code for changing the UID of a Chinese magic card ? Or is it not even possible to do with the hardware that I own ?

Thanks.