Pcscd not recognizing (cyberJack) USB card reader

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1

setting services.pcscd.enable = true; in configuration.nix, the device is not recognized:

[user@nixos:~]$ sudo systemctl status pcscd.socket
● pcscd.socket - PC/SC Smart Card Daemon Activation Socket
     Loaded: loaded (/etc/systemd/system/pcscd.socket; enabled; preset: ignored)
    Drop-In: /nix/store/61ys57ml6m7m611w80y372288brlglsi-system-units/pcscd.socket.d
             └─overrides.conf
     Active: active (listening) since Sat 2025-11-22 12:55:39 CET; 1h 10min ago
 Invocation: 850b2578593145a893c96564e3c8019a
   Triggers: ● pcscd.service
     Listen: /run/pcscd/pcscd.comm (Stream)
     CGroup: /system.slice/pcscd.socket

Nov 22 12:55:39 nixos systemd[1]: Listening on PC/SC Smart Card Daemon Activation Socket.

[user@nixos:~]$ sudo systemctl status pcscd.service
○ pcscd.service - PC/SC Smart Card Daemon
     Loaded: loaded (/etc/systemd/system/pcscd.service; linked; preset: ignored)
    Drop-In: /nix/store/61ys57ml6m7m611w80y372288brlglsi-system-units/pcscd.service.d
             └─overrides.conf
     Active: inactive (dead) since Sat 2025-11-22 14:05:41 CET; 36s ago
   Duration: 1min 4.875s
 Invocation: b37975d539cc492aa483dd71bcf1d5f2
TriggeredBy: ● pcscd.socket
       Docs: man:pcscd(8)
    Process: 3533 ExecStart=/nix/store/6mzqgk6vmk9aphhrmpqv2y11fr878cx1-pcsclite-with-polkit-2.3.0/bin/pc>
   Main PID: 3533 (code=exited, status=0/SUCCESS)
         IP: 0B in, 0B out
         IO: 0B read, 0B written
   Mem peak: 3.2M
        CPU: 28ms

Nov 22 14:04:37 nixos systemd[1]: Started PC/SC Smart Card Daemon.
Nov 22 14:05:41 nixos systemd[1]: pcscd.service: Deactivated successfully.

[user@nixos:~]$ pcsc_scan
PC/SC device scanner
V 1.7.3 (c) 2001-2024, Ludovic Rousseau <ludovic.rousseau@free.fr>
Using reader plug'n play mechanism
Scanning present readers...
Waiting for the first reader... - SCardGetStatusChange: Command cancelled.
2

What sort of device do you have? If its with a Yubikey, you want to add the plugin for it.

services.pcscd.plugins = [ pkgs.ccid ];
3

The relevant error using journalctl seems “was not an MTP device”. AI says:

The error “not an MTP device” in Linux occurs when the system detects a USB device but does not recognize it as a Media Transfer Protocol (MTP) device, which is needed for transferring files from devices like phones. To fix this, first, ensure your phone is unlocked and the USB connection is set to “File Transfer” or “Media device (MTP)”. If the problem persists, solutions include installing necessary packages like mtp-tools and gvfs-backends , checking for conflicting software, or creating a udev rule for the specific device.

and linux - disable MTP udev rules for specific device so it can be mount as a USB Mass Storage device - Super User details udev rules settings - quite complicated (for me).

Nov 23 09:28:53 nixos kernel: usb 1-3: USB disconnect, device number 2
Nov 23 09:28:55 nixos kernel: usb 1-3: new full-speed USB device number 4 using xhci_hcd
Nov 23 09:28:55 nixos kernel: usb 1-3: New USB device found, idVendor=0c4b, idProduct=0501, bcdDevice= 0.01
Nov 23 09:28:55 nixos kernel: usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Nov 23 09:28:55 nixos kernel: usb 1-3: Product: cyberJack RFID komfort1
Nov 23 09:28:55 nixos kernel: usb 1-3: Manufacturer: REINER SCT
Nov 23 09:28:55 nixos kernel: usb 1-3: SerialNumber: 0740753463
Nov 23 09:28:55 nixos mtp-probe[4075]: checking bus 1, device 4: "/sys/devices/pci0000:00/0000:00:02.1/0000:04:00.0/0000:05:08.0/0000:0b:00.0/0000:0c:0c.0/0000:13:00.0/usb1/1-3"
Nov 23 09:28:55 nixos mtp-probe[4075]: bus: 1, device: 4 was not an MTP device
Nov 23 09:28:55 nixos mtp-probe[4078]: checking bus 1, device 4: "/sys/devices/pci0000:00/0000:00:02.1/0000:04:00.0/0000:05:08.0/0000:0b:00.0/0000:0c:0c.0/0000:13:00.0/usb1/1-3"
Nov 23 09:28:55 nixos mtp-probe[4078]: bus: 1, device: 4 was not an MTP device
4

Good thinking. However for my Yubikey 5 smart card with gnupg, I have

  services.udev.packages = [ pkgs.yubikey-personalization ];
  programs.gnupg.agent = {
    enable = true;
    enableSSHSupport = true;
  };

set without the plugin and it works.

5

The device is question is https://shop.reiner-sct.com/chipkartenleser-fuer-die-sicherheitsklasse-3/cyberjack-rfid-komfort-usb

6

makes no difference. I guess, we have to work out udev rules. Any advice?

7

I guess you can find relevant udev rules here Making sure you're not a bot!

8

No need for messing with udev. From my config:

services.pcscd = {
    enable = true;
    plugins = [
      pkgs.ccid
      pkgs.pcsc-cyberjack  # Reiner SCT reader
      channels.unfree.pcsc-scm-scl011  # another reader
    ];
  };
9

I had to remove this and - it works! Even the AusweisApp does (it has to be started via the icon).

10

Thanks for the Info; it solved my problem too

11

Unfortunately, cyberJack has ceased to work. Any ideas?

sudo systemctl status pcscd.service
● pcscd.service - PC/SC Smart Card Daemon
     Loaded: loaded (/etc/systemd/system/pcscd.service; linked; preset: ignored)
    Drop-In: /nix/store/59lb6jmx5r1bqfrvhmzwkgckvh5gggk1-system-units/pcscd.service.d
             └─overrides.conf
     Active: active (running) since Fri 2026-07-03 14:26:35 CEST; 4min 45s ago
 Invocation: e920fea3ff4f4849b927c6bbc2960b37
TriggeredBy: ● pcscd.socket
       Docs: man:pcscd(8)
   Main PID: 21234 (pcscd)
         IP: 0B in, 0B out
         IO: 976K read, 0B written
      Tasks: 12 (limit: 37113)
     Memory: 5M (peak: 6.1M)
        CPU: 233ms
     CGroup: /system.slice/pcscd.service
             └─21234 /nix/store/9aqnmc9rk0xxf9346gc6jh6sl0lihyhc-pcsclite-with-polkit-2.4.>

Jul 03 14:26:35 nixos systemd[1]: Started PC/SC Smart Card Daemon.
Jul 03 14:26:36 nixos pcscd[21234]: CYBERJACK: Started
Jul 03 14:26:36 nixos pcscd[21234]: RSCT: Error on libusb_open: -3
Jul 03 14:26:36 nixos pcscd[21234]: RSCT: Error on libusb_open: -3
Jul 03 14:26:36 nixos pcscd[21234]: 00000000 ../src/readerfactory.c:1144:RFInitializeReade>
Jul 03 14:26:36 nixos pcscd[21234]: 00000051 ../src/readerfactory.c:371:RFAddReader() REIN>
Jul 03 14:26:36 nixos pcscd[21234]: 00000052 ../src/hotplug_libudev.c:527:HPAddDevice() Fa>
12

I finally got around to fixing this on my system. It seems that the pcsclite project started requiring to be run under a non-root user, which got reflected in this commit in Nixpkgs.

Since the pcsc-cyberjack package does not include udev rules for the card readers, the respective device files are owned by root:root so pcscd is not able to access them.

To fix it now, you can add the following udev rules manually:

services.udev.extraRules = ''                                                      
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0100", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0300", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0400", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0401", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0412", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0485", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0500", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0501", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0502", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0503", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0504", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0505", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0506", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0507", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0525", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0580", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="2000", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="0551", MODE="660", GROUP="pcscd"
  ATTR{idVendor}=="0c4b", ATTR{idProduct}=="2002", MODE="660", GROUP="pcscd"
'';

Those are from the rpm package that is distributed by Reiner SCT which has been linked above.
The correct fix would probably be to get this included in the pcsc-cyberjack package. I will have a look at that.