OSError: [Errno 19] ENODEV] on City Hub (60197) after Motor Initialization (Motor Works via Remote)

[BlueGuyOfficial]

The Problem:
​I am consistently encountering an OSError: [Errno 19] ENODEV] when trying to initialize a motor on the LEGO City Hub (part number 60197) using the Pybricks MicroPython firmware.
​The error occurs on the line: motor = Motor(Port.A) or motor = Motor(Port.B).
​Confirmed Facts (Troubleshooting Performed):
​Hardware is NOT faulty: The train motor and City Hub work perfectly when controlled using the official LEGO Powered Up Remote Control.
​Ultimate Software Reset Performed: I have fully reset the hub by flashing the Official LEGO Firmware (via the Powered Up App) and then reinstalling the latest Pybricks firmware.
​Port-Independent: The error occurs on both Port A and Port B when testing in the Pybricks REPL terminal.
​Connection Independent: The error persists even when attempting to run the script standalone (saved permanently to the hub and run without an active Bluetooth connection to the Editor).
​Conclusion:
​This points to a specific, deep-seated initialization bug within the Pybricks firmware itself that prevents the software from properly detecting a motor connected to the City Hub's ports, despite the hardware functioning correctly.

[laurensvalk]

Is it an original Lego motor, and if so, which one?

Pro tip: Please do not use AI to ask humans for help.

[BlueGuyOfficial]

It is the original LEGO City Hub from set 60197. When it has the official LEGO Firmware, it runs fine with the original remote controller.

[BertLindeman]

Hi,

Not sure if the remote has to do with motor initialization.

Do you have a short program with the definitions you use?
Something like

from pybricks.hubs import CityHub
from pybricks.pupdevices import DCMotor
from pybricks.parameters import Port
from pybricks.tools import wait
train_motor = DCMotor(Port.A)

train_motor.dc(50)
wait(1000)

Does this program help you?

Bert

[BlueGuyOfficial]

Yeah that program works

20251020_111029.mp4

[BertLindeman]

Thanks for the feedback.

So you had the wrong type of motor in your program, I assume?

[BlueGuyOfficial]

Yup, it was the wrong type of motor. I'm trying to get the train to accelerate and brake slowly, and I'm using this code for that:

# Importeer de benodigde Pybricks modules.
from pybricks.hubs import CityHub
from pybricks.pupdevices import DCMotor, Remote 
from pybricks.parameters import Port, Button, Color
from pybricks.tools import wait, StopWatch

# Initialiseer de hub, motor en afstandsbediening.
hub = CityHub()
motor = DCMotor(Port.B) 
remote = Remote()

# Stel de snelheidstrappen in.
snelheden = [0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
huidige_index = 0
huidige_snelheid = 0

# Loop oneindig
while True:
    # Haal de ingedrukte knoppen op
    pressed = remote.buttons.pressed()

    # --- KNOPPEN LOGICA ---
    if Button.RIGHT in pressed:
        huidige_index = min(huidige_index + 1, 10)
    elif Button.LEFT in pressed:
        huidige_index = max(huidige_index - 1, 0)
    elif Button.CENTER in pressed:
        huidige_index = 0

    # Haal de nieuwe doelsnelheid uit de array
    nieuwe_snelheid = snelheden[huidige_index]

    # Stuur alleen een commando als de snelheid is veranderd
    if nieuwe_snelheid != huidige_snelheid:
        if nieuwe_snelheid == 0:
            motor.brake()
        else:
            # GEFIXED: Gebruik motor.dc() voor vermogen (duty cycle)
            motor.dc(nieuwe_snelheid) 

        huidige_snelheid = nieuwe_snelheid

    # Kort wachten
    wait(100)

However, that code doesn't work very well. The result of the code is in the video:

20251020_114919.mp4

[dlech]

Button.RIGHT and Button.LEFT are the red buttons. It looks like you want either Button.LEFT_PLUS/Button.LEFT_MINUS or Button.RIGHT_PLUS/Button.RIGHT_MINUS instead.