If your USB serial adapter (NodeMCU, ESP32, Arduino, or FTDI cable) appears momentarily as /dev/ttyUSB0 or /dev/ttyACM0 when plugged into Ubuntu 22.04 / 24.04 and then instantly disappears, the pre-installed BRLTTY (Braille display support daemon) is claiming the USB device node.

Diagnosing BRLTTY Interference (dmesg)

Kernel Log Inspectionbash
$ dmesg | grep -i brltty
# Output: brltty: usbfs: interface 0 claimed by ch341
# Output: ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0

Resolution: Disable or Remove BRLTTY Package

If you do not require a Braille display device, remove brltty completely or mask its systemd services:

Terminal Fix Commandsbash
# Method 1: Remove brltty package completely (Recommended)
sudo apt remove -y brltty
 
# Method 2: Stop and mask brltty services without removing
sudo systemctl stop brltty-udev.service
sudo systemctl mask brltty-udev.service
sudo systemctl stop brltty.service
sudo systemctl mask brltty.service
 
# Reload udev subsystem rules
sudo udevadm control --reload-rules
sudo udevadm trigger