Arduino Nano 33 IOT 'west flash' failure

Sunanda Roy <sroy9@...>


While trying to execute a simple test program (samples/hello_world) on Arduino Nano 33 IOT (target) using Zephyr RTOS. I followed all installation steps and when I run the 'west flash' command in bootloader mode, I got this error: No device found on /dev/ttyACM0 (serial port).

After some online study, I find that I need to change permissions of serial port to 666 before every flash. Now when I follow the steps at (, I get the below error:
-- west flash: using runner bossac

SAM-BA operation failed

On the contrary, when I do NOT open the minicom terminal (in a separate window), I am able to flash successfully.

This allows me to successfully flash and verify sample programs which do not require any serial output (ex. samples/basic/blinky). But I am not able to see any output for sample programs like (samples/drivers/crypto) after a successful flash.

Please provide your suggestions to see the output of these sample programs on my desktop machine running Ubuntu 20.04.2 LTS.


William Fish

I have been seeing the same thing with the nano-33 Sense using windows. I had assumed it must be my set-up but this would indicate that there is an issue with serial output on the Nano boards.

Not sure where to start.