mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0: [Errno 2] No such file or directory: '/dev/serial/by-id/usb-1a86_USB_Serial-if00-port0'
This is your error. In the first place, this is an indication that the board does not correctly announce itself as an USB device on Linux OS level.
Follow the dmesg procedure and attach the output.