Well I just got around, after putting it off for a long long time, to updating my FC-300. One of the reasons that I waited so long is that the instructions given here in this thread made things seems a little more complicated than they need to be. So I have decided to write my experience here and maybe it will prove useful to someone.
(In case you have forgotten, the procedure for verifying the firmware of the FC-300 is to power up the unit or to power up the VG-99 to which the FC-300 is attached, while pressing both of the FC-300's Parameter keys.)
RRC2 Cable (or any non-crossover Cat 5 Ethernet cable will work too.)
5-pin DIN midi cable.
Here is the actual procedure:
I took a VG-99 with NO USB cable attached.
I used a 5-pin DIN midi cable to connect the 5-pin DIN MIDI output of my RME Multiface to the 5-pin DIN MIDI input of the FC-300. (I.e. no USB or USB/MIDI cable was necessary.)
I connected the FC-300 to the VG-99 with the RRC2 cable - although any Cat 5 Ethernet (non-crossover) cable will work. This is to power up and power down the FC-300 by powering up and powering down the VG-99.
While holding the EXIT and WRITE buttons on the FC-300, I powered up the VG-99 and I continued to hold the EXIT and WRITE buttons until the LED display on the FC-300 read "UPd". The FC-300 is now in Update Mode.
I then launched the updSMF Player and
1) for my MIDI Out Device I chose "Multiface Midi";
2) I navigated to the folder where the midi files of the v1.02 update were located; and
3) I clicked on the "Scan SMF" button and the updSMF Player found and listed all the midi files in the folder.
4) I clicked the "Send" button.
The FC-300 immediately showed me a message saying "Receiving" (or something similar, I don't recall exactly) and after a few minutes, it send me a message saying "Completed". (This is a pretty quick update, unlike updating the VG-99.)
I then powered off the VG-99 which also powered off the FC-300, and then while holding both parameter keys on the FC-300 I powered up the VG-99 again. The FC-300 told me that the installed firmware was now v1.02.
The main points are that a USB or USB/MIDI cable is not needed, and that the VG-99 can act as a power supply for the FC-300 while updating (as it usually does, anyway.)