termios.error: (5, 'Input/output error')

[finlopes97]

When trying to run gv2thermal_printer_config.py returns error:

pi@raspberrypi:~/zj-58 $ sudo python gv2_thermal_printer_config.py
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/dist-packages/serial/serialposix.py", line 398, in _reconfigure_port
    orig_attr = termios.tcgetattr(self.fd)
termios.error: (5, 'Input/output error')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/pi/zj-58/gv2_thermal_printer_config.py", line 12, in <module>
    ser = serial.Serial(PORT, BAUD, timeout=0.5)
  File "/usr/local/lib/python3.9/dist-packages/serial/serialutil.py", line 244, in __init__
    self.open()
  File "/usr/local/lib/python3.9/dist-packages/serial/serialposix.py", line 332, in open
    self._reconfigure_port(force_update=True)
  File "/usr/local/lib/python3.9/dist-packages/serial/serialposix.py", line 401, in _reconfigure_port
    raise SerialException("Could not configure port: {}".format(msg))
serial.serialutil.SerialException: Could not configure port: (5, 'Input/output error')

Printer is this model "Mini thermal printer." Flow control listed on the test sheet is "HW Flow Ctrl" so I'm trying to turn on xon/xoff following this tutorial. Baudrate is 19200.

[klirichek]

That is not related to this project.
That is just cups filter, and includes exactly two files - filter itself + ppd file.
It has nothing to deal with python, serial, and even any interface of how actual printer is plugged.