I just tested my prototype for a new HiFiBerry DAC HAT, but have some problems accessing the EEPROM. I was looking for a hardware problem. After some hours of debugging, I noticed that the I2C communication seems to work. The EEPROM correctly sets the ACK bit at the end of the I2C communication. However, the "i2cxxx" commands from command line still fails. I guess, this is somewhere blocked in the Linux kernel. How can I access the EEPROM on the HAT?