Serial Console Troubleshooting
No output on the serial port
1. Verify the cable
Many USB-C cables are charge-only and carry no data lines. Use a cable explicitly rated for data transfer, or test with a known-good cable.
2. Identify the correct port
After connecting the USB-to-serial adapter:
If nothing appears, the driver may not be loaded. Check dmesg:
A recognised adapter shows something like:
3. Connect with the correct settings
Baud rate 115200, 8 data bits, no parity, 1 stop bit (8N1):
4. Check permissions
If you get Permission denied on /dev/ttyUSB0:
Log out and back in for the group change to take effect.
5. Power on the board
Connect the serial adapter before powering the board to avoid missing early boot output.
Garbled characters on the terminal
The baud rate on the terminal does not match the board's output. Engicam boards use 115200 baud.
Verify your terminal emulator is set to 115200 and reconnect. In picocom, you can change baud rate at runtime with Ctrl+A B.
Serial connects but no login prompt appears
U-Boot output is visible but Linux doesn't start
The kernel may have booted but the serial console device is misconfigured. Check the console= parameter in bootargs:
It must include the correct UART device and baud rate, e.g.:
The UART number varies by SoC family:
| SoC | Typical console |
|---|---|
| i.MX6, i.MX8 | ttymxc0 or ttymxc1 |
| i.MX9x | ttyLP0 or ttyLP1 |
| STM32MP2 | ttySTM0 |
Linux boots but getty is not started
Check if the serial getty service is active:
Enable it: