def METHOD_NAME(self):
    """
    Retrieves the firmware version of the component
    Returns:
        A string containing the firmware version of the component
    """
    if self.index == 0:     # BIOS
        bios_ver = self._get_command_result(BIOS_QUERY_VERSION_COMMAND)
        if not bios_ver:
            return 'NA'
        else:
            return bios_ver
    elif self.index < 5:    # CPLD
        return self._get_cpld_version(self.index)
    elif self.index == 5:   # FPGA
        return self._get_fpga_version()