need only block 0

[GrimorJander]

hi. i run your sketch , dumping was ok, but when writing a tag always stop at block 4.

Insert new card...
Card UID: 7A 09 81 10
PICC type: MIFARE 1KB
Authenticating using key A...
Authenticating again using key B...
Writing data into block 4

FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

Authenticating using key A...
PCD_Authenticate() failed: Timeout in communication.

Its posible to get a sketch that only read and write UID (block 0) in a easier way?

[michalmonday]

Hi, I wish I could help you but I have no idea how, I'm not familiar with rfid in general. I think it would be the best if you used the following example from rfid library (updated one) and see whether it works with it:
https://github.com/miguelbalboa/rfid/blob/master/examples/ReadAndWrite/ReadAndWrite.ino

In case if that example doesn't work then it would be much better if you created the issue there (or look for similar ones). I'm sorry for replying so late.