On the TARS SAO there are two quiic connectors, one was meant to connect to the I2C0 and the other to I2C1 capable pins of the RP2040 module. Sadly I mixed up pins and numbers and managed to connect both to I2C1 pins, just different ones. So best to ignore the SAO QUIIC connector. A rough I2C scanner is now running on TARS, making it possible to check for things on the bus. I just hope the badge RPI gets along well enough with a multi-master situation.