@vleeuwen I think you are right. I could not read the numbers well, printed on the EEPROM. And when I googled the datasheet, I found some SPI versions as well.
What I focused on in my documentation was more on how the different ports work electrically in terms of what you can connect and how. I could not find any documentation about that besides the vague describtion in the fischertechnik docs.
I did not focus on how to install a different firmware which is also besides my expertise. I get the whole JTAG thing, but I would be scarred to brick it
![Zwinkern ;-)](./images/smilies/icon_e_wink.gif)
ASks' site is a good find. I hope he extends on it some day.