Does anyone know if and how AVRDUDE is used ?  

Danke für die Info Sorry, für das Mißverständniss  Ich möcht  18=SDA und 19=SCL benutzen. Gruß Heinz

Dear Russin Sir Bullar , we are sorry to hear that the OLED is not working at all. For replacement please contact customerservice ( service@elektor.com ) . For the software related questions: the Atmega comes with a preprogrammed Arduino bootloader. If you load the sketch you can compile amd upload it using the arduni IDE, as the board behaves like a Arduino Leonardo. Also you should have the Firmware 1.2 already preprogrammed to the chip and be able to use a termial ( like putty , hterm, cutecom ,.... ) to access the serial command line interface ( Parameter: 11500 Baud, 8 Databits, no parity , 1 Stopbit ). Best regards ElektorLabs  

Hi Laurent, a first test said it's ok, it seems to work. I will do more tests if I have more time. Thank you very much Hans

@Heinz2 Wie denn? Du musst die Frage von ElektorLabs schon korrekt beantworten, wenn du willst, dass man dir hilft! 18=SDA und 19=SCL?