Arduino no response over serial

I’m running the test code on an arduino mega unchanged. I have the arduino connected to the GPIO 1 and 2 for tx and rx. I get no response.
I saw this commetn with no details: setting of the working mode of the GPIOs
Also I was unable to configure the odrive to one of the hardware serials.
Any help on these subjects?

Can you show us what you attempted for the Arduino Mega hardware serial? That’s probably your best bet for reliable communication.