@stephane-clavel Do the RUN leds blink? Did you save the direct switch configuration to NV ram or do you set ip up again after boot? Can you provide the output of i2cdetect -y 1 ?
it seems you have not some kernel modules loaded. Try lsmod command - you should see unipi, at24 and i2c_dev modules loaded. If not, follow the steps below.
As the first step, try to reinstall appropriate package (assuming you have the unipi repository already sourced):
As the second step, reboot the controller.
@tomas_hora all good, it just needed a good apt-upgrade :)