The only tool to download firmware to the MC-4 is the Sercos Firmware Assistant. There used to be an old DOS based Bootloader program, but it is long obsolete and I don't know where you would find it. It should not be needed anyway. How are you trying to use the MC-4? It is meant to be connected to a ELAU motion controller (Max-4, C200, C400, or C600). If it is not connected, it is likely the error LED will be flashing.