nRF52 edit nfc tag

Question

Hello, 
 I have a question about the NFC tag. In the example nrf_url_record_pca10040 there is a part where the url will be written in the tag 
 
 err_code = nfc_uri_msg_encode(
NFC_URI_HTTP_WWW,
(uint8_t *) url,
sizeof(url),
ndef_msg_buf,
&len); 
 
 However when I try to write something from outside the code, with for example my phone I get the error that the tag is write protected. (The tag is delivered with the DK) 
 My question is: Is it possible to remove the lock, or to rewrite the url from outside?
If so, please tell me how I can do this. 
 Thanks in advance

Tim · Accepted Answer

Thansk for the response, 
 I already solved this issue.
I changed the lock bytes and write protect bytes.
By setting these location to 0x00 and 0x0000. 
 #define LOCK (*(uint16_t volatile *)(0x2000220A))
#define WRITEPROTECT (*(uint8_t volatile *)(0x2000220F))
 
 And by checking if its a write request 
 if (m_nfc_rx_buffer[0] == 0xA2)
 
 Then by using the function: 
 const char ack = 0x0A;
hal_nfc_send(&ack,1);
 
 To send a response. 
 Kind regards, 
 Tim Smits