(Trying to use the library on windows)
Using os.join() results in funky paths like 'radio_fw\\\\XB3-24A/XB3-24A_2003-th.xml' which cannot be found and throw exceptions.
For looking at zipfile contents, i think you need to force the slash type

I changed to self._fw_xml_file = _FW_DIR_NAME + "/" + self._fw_xml_filename and the code executed fine