Root login invalid after watchdog triggered reboot

Colibri imx6ull 512 on custom carrier board
Toradex reference image minimal


we have a strange effect while using the colibri hardware watchdog on /dev/colibri-watchdog.
We tested/triggered the watchdog with a python script. This is working. When stopping the feeding the system restarts. So far so good. But if we have an opened file (e.g. nano dummy.txt) and the watchdog reboots in background, we are not able to login after reboot. We get a login prompt but the root credentials (using pwd) are not accepted anymore: Wrong username or password.

Does anyone knows this effect?

Hi @acb ,

Thanks for your question.

Can you maybe state which HW version your module has? Furthermore, please also state which version of the Toradex reference minimal image you used.

Do you see the same behaviour on a Toradex carrier board?

Best Regards

Hi @kevin.tx ,

thank you for the response. I Think this issue has been “resolved”. After the reboot caused by watchdog, something in the UART serial console has changed. Due to this, pasting of e.g. passwords wont work anymore…until you restart the terminal (reset the session). After that, everything is working fine again.

Best regards


Hi @acb ,

All right, thanks for confirming.

If you have more questions in the future related to this feel free to post it here.

Best Regards