 }
 
 void playMp3() {
+  // IO takes time, reset watchdog timer so it does not kill us
+  yield();
   SdFile file;
   SD.vwd()->rewind();
 

  if (contentSize < bufferSize) {
    bufferSize = contentSize;
  }
  for (byte i = 0; i < bufferSize; i++) {
    buffer[i] = newContent[i];
  }

  // Write block
  Serial.print(F("Writing data to block: ")); Serial.println(newContent);
  status = (MFRC522::StatusCode) mfrc522.MIFARE_Write(absoluteBlock, buffer, 16);
  if (status != MFRC522::STATUS_OK) {
    Serial.print(F("MIFARE_Write() failed: "));
    Serial.println(mfrc522.GetStatusCodeName(status));

    key.keyByte[i] = 0xFF;
  }

  Serial.print(F("Using rfid key (for A and B): "));
  print_byte_array(key.keyByte, MFRC522::MF_KEY_SIZE);
  Serial.println();

  //Initialize the SdCard.
  if (!SD.begin(SD_CS)) {
    Serial.println(F("Could not initialize SD card"));
    SD.initErrorHalt();
  }

  // initialise the music player
  if (!musicPlayer.begin()) { // initialise the music player
    Serial.println(F("Couldn't find VS1053, do you have the right pins defined?"));
    while (1) delay(500);
  }
