Reply To: SCD30 on Pi gives Remote I/O error, should I write I2C in Python with bit-bang?

I moved it to bus 3 with an overlay, and for 2 days there has not been a single Errno 121. I had forgotten the pull-ups; on first boot i2cdetect came back empty, and once I added the 4.7k resistors it showed up. Good thing I didn’t get into writing bit-bang.