docs: def respond_fw_config(self, msg):
          """Respond to a firmware config request."""
          (req_fw_type,
           req_fw_ver,
           req_blocks,
           req_crc,
           bloader_ver) = fw_hex_to_int(msg.payload, 5)
          _LOGGER.debug(
              'Received firmware config request with firmware type %s, '
              'firmware version %s, %s blocks, CRC %s, bootloader %s',
              req_fw_type, req_fw_ver, req_blocks, req_crc, bloader_ver)
          fw_type, fw_ver, fware = self._get_fw(
              msg, (self.requested, self.unstarted))
          if fware is None:
              return None
          if fw_type != req_fw_type:
              _LOGGER.warning(
                  'Firmware type %s of update is not identical to existing '
                  'firmware type %s for node %s',
                  fw_type, req_fw_type, msg.node_id)
          _LOGGER.info(
              'Updating node %s to firmware type %s version %s from type %s '
              'version %s', msg.node_id, fw_type, fw_ver, req_fw_type,
              req_fw_ver)
          msg = msg.copy(sub_type=self._const.Stream.ST_FIRMWARE_CONFIG_RESPONSE)
          msg.payload = fw_int_to_hex(
              fw_type, fw_ver, fware['blocks'], fware['crc'])
          return msg