Digging up a bit of an old thread, but ive been researching info about the counterfit FTDI chips that have been in circulation in the last 6 months and stumbled on this thread.

I believe the issues is just that, counterfit chips. FTDI appear to have modified their drivers to detect the bad silicon and cause them not to work. This is why the old driver that pre-dates the forgeries hitting the market still works.

According to this site http://zeptobars.ru/en/read/FTDI-FT2...-fake-supereal the forgeries have been made to be API compatible but not a copy of FTDIs silicon at all.

It seems the market has been flooded and many genuine companies have been stung. Ive also been stung, and it seems one must now be careful to buy only though official distribution channels. There are other reports around the net of the same.