Thanks for your advice! Since I am on holiday I do not have access to an oscilloscope. For now I bought the official programming adapter from knjn. When it is delivered and I am back at work I will compare the signals of the official adapter to my FTDI chip with an oscilloscope. I will let you guys ...

Hello everyone, I tried to reprogramm my Pluto-IIx HDMI board over the serial interface. Unfortunately with no success. I used a FTDI chip FT232R and connected it in this way: FTDI GND to Pluto GND FTDI Vcc (5V) to Pluto Vunreg FTDI Rx (3V3) to Pluto Tx FTDI Tx (3V3) to Pluto Rx Then I opend FPGAcon...