I think you have just hit the nail on the head!!!
In order to set the i2c baudrate to 400kHz in the rapsberry I use
apparently there's an issue with this setting in the RPi device tree, and the number you set gets modified. A more complete explanation in a german article linked here: https://www.raspberrypi.org/forums/viewtopic.php?t=197707
I now realize that we have never explicitly told no one to increase the default baudrate on the RPi. This might be a game-changer. Let us know how it goes.
Did you try to measure the actual baudrate with an oscilloscope? you can use the
i2cdetect -y 1 command to make the RPi issue some i2c readings, and put your prove on the SCL line (
TP9 on the Chordata Hub)
PS: Does the phrase hit the nail on the head actually mean something in english?? 😅