Hello @tak ,
Thanks for your fast answer.
I have found a thread with a similar issue, and the cause seemed to be the serial adapter (USB-RS232).
Which one are you using?
I have another additional question: are you using one of our serial cables (10 pin header to 9 pin SUB-D) or did you make it yourself?
If so, could you please share with us the schematics of such cable?
Best regards,
Josep