[HELP] Inconsistent NTAG424 DNA reading with uTrust 3720F on Debian 13

[neorai]

Environment

OS: Debian 13 (Trixie)
Desktop Environment: KDE Plasma (X11)
Reader: uTrust 3720F
Tag Type: NTAG424 DNA

Description

I am experiencing inconsistent behavior when trying to read NTAG424 DNA tags using a custom script (nfc_reader.py). The issue seems to trigger after the system has been powered off or during a fresh boot.

Observed Behavior

The Issue: After starting the system, the script fails to read the tag's data payload/records, successfully retrieving only the UID.
The "Workaround": After several system reboots and physically reconnecting the uTrust reader multiple times, the script suddenly starts working perfectly again.
Expected Behavior: Consistent data reading from the NTAG424 DNA tags upon script execution, regardless of system uptime.

Context & Suspicions

I suspect this might be related to how I am initializing the library or a potential conflict with the pcscd service or driver handling in Debian 13. I am concerned that I might be misusing the library's connection lifecycle.

Reproducing the issue

Cold boot the machine.
Connect the uTrust 3720F reader.
Run nfc_reader.py.
Only the UID is returned; data read fails.
Re-plug reader and reboot until it works.

ntag_info.txt
nfc_reader.py
uTrust_372X_F_Product_Manual.pdf

[LudovicRousseau]

What is the error returned by PySCard? What PySCard function returns this error?

[neorai]

It doesn’t always happen and I don’t know why. For the past few days it hasn’t happened—maybe the reader isn’t working properly.

2026-02-16 10:46:00 [INFO] Lector NFC - Identiv uTrust 3700 / NTAG424 DNA
2026-02-16 10:46:00 [INFO] Enviando datos a http://localhost:8080/api/nfc
2026-02-16 10:46:00 [INFO] Esperando tarjetas... (Ctrl+C para salir)
2026-02-16 10:46:00 [INFO] --------------------------------------------------
2026-02-16 10:46:00 [INFO] Lector encontrado: Identiv uTrust 3700 F CL Reader [uTrust 3700 F CL Reader] (55022536201800) 00 00
2026-02-16 10:46:12 [INFO] ==================================================
2026-02-16 10:46:12 [INFO] TARJETA DETECTADA
2026-02-16 10:46:12 [DEBUG] TX []: FF CA 00 00 00
2026-02-16 10:46:12 [DEBUG] RX []: SW=9000 data=04 43 5A 8A 2B 16 90
2026-02-16 10:46:12 [INFO] UID: 04 43 5A 8A 2B 16 90
2026-02-16 10:46:12 [DEBUG] TX [SELECT_NDEF_APP]: 00 A4 04 00 07 D2 76 00 00 85 01 01 00
2026-02-16 10:46:12 [ERROR] Error leyendo NDEF: Failed to transmit with protocol T1. Transaction failed.: Transaction failed. (0x80100016)
Traceback (most recent call last):
File "/home/rai/nfc/nfc_reader.py", line 324, in process_card
ndef_raw = read_ndef(connection)
File "/home/rai/nfc/nfc_reader.py", line 149, in read_ndef
_, sw1, sw2 = transmit_apdu(
~~~~~~~~~~~~~^
connection, APDU_SELECT_NDEF_APP, "SELECT_NDEF_APP"
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/home/rai/nfc/nfc_reader.py", line 94, in transmit_apdu
data, sw1, sw2 = connection.transmit(apdu)
~~~~~~~~~~~~~~~~~~~^^^^^^
File "/home/rai/.local/lib/python3.13/site-packages/smartcard/CardConnectionDecorator.py", line 88, in transmit
return self.component.transmit(command, protocol)
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
File "/home/rai/.local/lib/python3.13/site-packages/smartcard/CardConnection.py", line 179, in transmit
data, sw1, sw2 = self.doTransmit(command, protocol)
~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
File "/home/rai/.local/lib/python3.13/site-packages/smartcard/pcsc/PCSCCardConnection.py", line 307, in doTransmit
raise CardConnectionException(
...<5 lines>...
)
smartcard.Exceptions.CardConnectionException: Failed to transmit with protocol T1. Transaction failed.: Transaction failed. (0x80100016)
2026-02-16 10:46:12 [INFO] Sin datos NDEF

[LudovicRousseau]

SCARD_E_NOT_TRANSACTED is the normal error when the communication fails between the reader and the card.
It is not surprising to get this error with contactless cards, depending on the environment.

I do not see any issue with PySCard here.