Flashed one of the Gotek units tonight using the 10.5a firmware.
I used a PL2303HX serial adapter:
and the SFR1M44-U100K model gotek:
Couldn't get the STM software to recognise the emulator at all under Win7_X64.
Tried the STM software in a WindowsXP virtual machine using VMware, recognised the emulator first go.
Didn't require a separate 5V power supply, just used the 5V from the USB-Serial adapter.
Formatted a 4GB USB stick in FAT32, and copied the selector.adf to the root directory.
Worked exactly as expected on my 500, 600.
On my unexpanded 1200, the selector program fails to load with a return code of "10". Oddly, running it a second time from the CLI works without error.
A great, and very inexpensive solution.
Thanks again H.M.!!