March 5, 2017 at 4:01 pm #22864
Hard to say for sure. An issue with the Peggy (for example an incomplete solder joint or backwards component somewhere) can sometimes create a programming error, even when everything else is working properly.
Did your adapter come with any documentation about which pin is which? Not every FTDI adapter has the pins in the same order, so the first thing to check would be to make sure that your device has a 1:1 match between its pin order and that of the standard FTDI cable.
Second, at $3.30 (about what it would cost us to buy the chip and connectors in large quantity — without pcb or assembly or margin), there’s more than a little chance that this is a counterfeit FTDI chip– FTDI has a long-running cold war with the counterfeit manufacturers, and has various ways to detect and disable devices like this from within the driver.