The replacement ROM for that process can often be found pre-burned on eBay too.
Also at the moment an SFG-05 is being auctioned there, but I have no idea whether ending price will be a reasonable one: https://www.ebay.com/itm/324676947929 (not my listing, just FYI)
That is actually a factory upgraded SFG-01->SFG-05 (or it may just be an SFG-01 that someone put in the box after upgrading to an SFG-05). I have seen one factory upgrade before (it was mounted in my CX-7M). Exterior was also like the SFG-01. It has a riser board for the ROM.
I think I have an SFG-01 available if you want to perform the upgrade yourself, I will check my inventory.
Like I said it may very well be a factory upgraded version. I imagine at the time they released the SFG-05 they had some stock SFG-01’s that would no longer sell (obviously) and they retrofitted them to SFG-05’s.
That is actually a factory upgraded SFG-01->SFG-05 (or it may just be an SFG-01 that someone put in the box after upgrading to an SFG-05). I have seen one factory upgrade before (it was mounted in my CX-7M). Exterior was also like the SFG-01. It has a riser board for the ROM.
Someone is going to be awfully disappointed if that turns out to be an SFG-01 in an SFG-05U box! I was watching that same auction out of curiosity.
As long as you don’t care about Yamaha’s software much, the SFG-01 and SFG-05 are equal in terms of FM and MIDI hardware capabilities. Just the Yamaha software support is lacking due to it having MBIOS 1.0 instead of MBIOS 2.0, but that does not matter to e.g. VGMPlay at all. So depending on what you want to use it for the SFG-01 is not a bad module to own, even if it hasn’t been upgraded.
But since the listing’s description speaks explicitly of the MBIOS 2.0 one could presume that this person knows what they’re talking about and has confirmed it is a unit with MBIOS 2.0 upgrade. Better to just send them a message to ask up-front of course.
p.s. I own a “factory” upgraded SFG-01 too. Note the factory part is speculation, but it looks professionally done and the ROM is modified by someone who knew the un-documented details of the differences between the YM2151 OPM and YM2164 OPP, so I concur with the theory that it is most likely an upgrade performed by Yamaha.
Yeah, I currently have the SFG-01, but I am reluctant to attempt the ROM upgrade. I have the skills and tools for this, but not the time. Mainly I want to be able to "Play" the CX5M from other MIDI hardware. If I don't find one soon, I will probably go the ROM upgrade route, though the documentation seems a bit difficult to follow.
Likely not news and a bit off-topic, but a Yamaha FB-01 module is very very similar to SFG-05 in FM capability and works stand-alone as a MIDI synthesizer. They seem a bit easier to find than SFG-05 right now. I have both and find I mostly use the FB-01 when the source is MIDI input from another device as the SFG-05 still requires typing CALL MUSICA or similar to put it into MIDI synthesizer mode (its firmware doesn't autostart unlike SFG-01)
