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Serial port and driver issues

Serial issues are a high-frequency cause of flashing failures. The serial port is used to observe the device boot log. This page collects common serial issues on Ubuntu and macOS by symptom.

Environment setup first

This page assumes you have completed environment setup for each platform and installed the drivers and dependencies (for the CH340N driver on macOS, see macOS environment). If not configured yet, complete the environment setup for the relevant platform first, then troubleshoot as described here.

Ubuntu serial garbled output

Symptom: after an Ubuntu laptop connects to the device, the serial output is garbled.

Cause: the default Ubuntu CH340N driver has compatibility issues when connecting at the 921600 baud rate.

Solution: install the official CH340N driver.

  1. Download the official serial driver CH340N driver.
  2. Modify ch341_tty_driver->name = "ttyUSB";.
  3. Recompile and install the driver.

macOS driver residue still causing garbled output

Symptom: the official driver has been installed per macOS environment → Install the CH340N driver, but the device still shows tty.usbserial* and the serial output is still garbled.

Cause: the default macOS driver CH34xVCPDriverApp was not fully uninstalled and conflicts with the new driver.

Solution:

  1. Uninstall the residual CH34xVCPDriverApp: move it to Trash and empty it.
  2. Restart the system.
  3. Reinstall the CH340N driver; see macOS environment → Install the CH340N driver.

More issues

If this page does not cover your case, visit the D-Robotics developer forum for help.