Non responsive screen menu - what I did to fix

[benharnden]

non responsive screen after install and reinstall several time.

2025-12-22 23:43:34,549 - ERROR - Failed to connect to display: No baud rate suited
2025-12-22 23:43:34,550 - ERROR - Failed to connect to display: No baud rate suited
2025-12-22 23:43:34,550 - ERROR - Error in listen(): No baud rate suited
2025-12-22 23:43:34,554 - ERROR - Traceback (most recent call last):
File "/home/mks/display_connector/display.py", line 1143, in listen
await self.display.connect()
File "/home/mks/display_connector/src/communicator.py", line 40, in connect
await self.display.connect()
File "/home/mks/display_connector/src/tjc.py", line 183, in connect
await self._try_connect_on_different_baudrates()
File "/home/mks/display_connector/venv/lib/python3.13/site-packages/nextion/client.py", line 205, in _try_connect_on_different_baudrates
raise ConnectionFailed("No baud rate suited")
nextion.exceptions.ConnectionFailed: No baud rate suited

I changed the BUADRATE to [115200] in constant.py and then get new error :

2025-12-22 23:43:50,566 - ERROR - Error in subscription or stream processing: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'
2025-12-22 23:43:50,567 - ERROR - Error in listen(): int() argument must be a string, a bytes-like object or a real number, not 'NoneType'
2025-12-22 23:43:50,579 - ERROR - Traceback (most recent call last):
File "/home/mks/display_connector/display.py", line 1195, in listen
await self.handle_status_update(data)
File "/home/mks/display_connector/display.py", line 1901, in handle_status_update
self._update_misc_states(new_data, data_mapping)
~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/mks/display_connector/display.py", line 1932, in _update_misc_states
self.filament_sensor_state = int(sensor_data.get("enabled", 0)) == 1
~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'

I then changed the block out in display.py line around 1931ish to :

    if f"filament_switch_sensor {self.filament_sensor_name}" in new_data:
        sensor_data = new_data[f"filament_switch_sensor {self.filament_sensor_name}"]
        enabled = sensor_data.get("enabled")
        self.filament_sensor_state = int(float(enabled)) == 1 if enabled is not None else False

And the display now works perfect for me!

[MercYuriy]

i used ai to solve a similar issue. THese are the steps that made it work for me so far:

Fix: Elegoo Neptune 4 / 4 Max touchscreen stuck on firmware update (OpenNept4une)

(Works on Debian 12 / Armbian Bookworm setups)

Symptoms

Printer + Klipper + Fluidd work

Touchscreen stuck on “firmware update” screen or blank

Happens after running updates via Fluidd / system updates

No hardware changes made

Root cause (confirmed)

The OpenNept4une touchscreen bridge (display.service) runs inside a Python venv

System updates removed or broke Python systemd bindings

Result: display.service crashes → screen never exits update mode

Step-by-step fix (safe, non-destructive)
1️⃣ SSH into the printer
ssh mks@<printer_ip>

2️⃣ Confirm the failure (optional but useful)
journalctl -u display.service -n 50 --no-pager

If you see:

ModuleNotFoundError: No module named 'systemd'

you’re in the exact failure state this fixes.

3️⃣ Stop the display service
sudo systemctl stop display.service
sudo systemctl reset-failed display.service

4️⃣ Install required OS packages

(these do NOT touch Klipper or configs)

sudo apt update
sudo apt install -y python3-systemd pkg-config libsystemd-dev

Why:

python3-systemd → system bindings

libsystemd-dev + pkg-config → required to build venv bindings

5️⃣ Install systemd bindings into the display venv

(This is the critical part most guides miss.)

/home/mks/display_connector/venv/bin/pip install --upgrade pip
/home/mks/display_connector/venv/bin/pip install systemd-python

6️⃣ Verify the fix BEFORE restarting anything
/home/mks/display_connector/venv/bin/python -c "import systemd.daemon; print('systemd import OK')"

You must see:

systemd import OK

If not → stop here and recheck step 4.

7️⃣ Start the display service
sudo systemctl start display.service
systemctl status display.service

Expected:

Active: active (running)

8️⃣ Reboot
sudo reboot

Expected result

Touchscreen boots normally

No firmware update loop

Screen connects cleanly to Moonraker

Noticeably faster and more stable UI than before

Why this works (short explanation for GitHub)

OpenNept4une’s touchscreen bridge uses a venv, not system Python

Updates removed systemd bindings the venv depends on

Service silently crashed → screen stayed in update mode

Installing bindings into the venv restores the bridge completely

Prevention tip

After updates, if the screen breaks:

journalctl -u display.service -n 50 --no-pager

Check software first — the screen is almost never actually bricked.