Possible conflict on I2C mux
I2C mux (IC80) can be controlled by both MMC and FPGA.
Example scenario leading to a bug:
1. FPGA sets I2C mux
2. MMC changes mux setting and does I2C transaction
3. FPGA tries to access device behind the mux
To avoid this we could add second I2C mux - FPGA and MMC would have separate I2C multiplexers.