Merge pull request #449 from DidierA/hfsniff-fix

nfc_tag_14a_event_callback(): Fixes wrong reported length when sniffing

CHANGELOG.md

@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file.
 This project uses the changelog in accordance with [keepchangelog](http://keepachangelog.com/). Please use this to write notable changes, which is not the same as git commit log...
 
 ## [unreleased][unreleased]
+ - Fix wrong data reported by hf 14a sniff on frames containing more than 7 parity bits (@DidierA)
  - Added MIFARE Ultralight C authentication and emulation (@Foxushka)
 
 ## [v2.2.0][2026-07-04]

firmware/application/src/app_cmd.c

@@ -2708,14 +2708,12 @@ static data_frame_tx_t *cmd_processor_hf14a_4_reader_apdu(uint16_t cmd, uint16_t
     }
 
     /* Copy data portion (strip PCB + CRC), then handle chaining */
-    uint8_t blk_num = 0;
     uint8_t resp_pcb = resp_buf[0];
     uint8_t dlen = resp_bytes - 3; /* subtract PCB(1) + CRC(2) */
     if (dlen > 0 && resp_chain_len + dlen < sizeof(resp_chain)) {
         memcpy(&resp_chain[resp_chain_len], &resp_buf[1], dlen);
         resp_chain_len += dlen;
     }
-    blk_num ^= 1;
 
     /* ISO14443-4 chaining: PCB bit5 (0x20) set means more blocks follow */
     while (resp_pcb & 0x20) {
@@ -2738,7 +2736,6 @@ static data_frame_tx_t *cmd_processor_hf14a_4_reader_apdu(uint16_t cmd, uint16_t
             memcpy(&resp_chain[resp_chain_len], &resp_buf[1], dlen);
             resp_chain_len += dlen;
         }
-        blk_num ^= 1;
     }
 
     return data_frame_make(cmd, STATUS_HF_TAG_OK, resp_chain_len, resp_chain);

firmware/application/src/rfid/nfctag/hf/nfc_14a.c

@@ -699,13 +699,8 @@ void nfc_tag_14a_event_callback(nrfx_nfct_evt_t const *p_event) {
                 uint32_t amt  = NRF_NFCT->TXD.AMOUNT;
                 uint16_t tx_bytes = (amt >> NFCT_TXD_AMOUNT_TXDATABYTES_Pos)
                                     & (NFCT_TXD_AMOUNT_TXDATABYTES_Msk >> NFCT_TXD_AMOUNT_TXDATABYTES_Pos);
-                uint16_t tx_bits_rem = (amt >> NFCT_TXD_AMOUNT_TXDATABITS_Pos)
-                                       & (NFCT_TXD_AMOUNT_TXDATABITS_Msk >> NFCT_TXD_AMOUNT_TXDATABITS_Pos);
-                uint16_t tx_bits = (tx_bits_rem > 0)
-                                   ? ((tx_bytes - 1) * 8 + tx_bits_rem)
-                                   : (tx_bytes * 8);
-                if (tx_bits > 0 && tx_bytes <= MAX_NFC_TX_BUFFER_SIZE) {
-                    m_tx_sniff_cb(m_nfc_tx_buffer, tx_bits);
+                if (amt > 0 && tx_bytes <= MAX_NFC_TX_BUFFER_SIZE) {
+                    m_tx_sniff_cb(m_nfc_tx_buffer, amt);
                 }
             }
             break;