Hello,
First of all, I want to note that the properly name of the native Ponyprog2000 hardware programmer is "SI-Prog" and not "SI_Prog".
Also, talking about:
"Please note that while USB-to-serial adapters work under certain circumstances, this slows down operation considerably."
Well, I for one, I understand by "considerably" that the operation will do hours, instead of minutes. The sadly truth is that operation will be epic slow. If I remember right, that EEEPC's W25X40, which I flashed, is not a huge flash, just 4M. Still, it was flashed in cca 27 hours.
Then, yes, PONY_SPI works fine over an PL2303 USB/serial adapter, under Linux, but its job is epically slow...
So, I believe that is right to warn the user that he have to wait a very very long time.
All the best, Virgil.