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Urgent: ADAU1442 self-boot operation failes


ADAU1442 fails self-boot  at power up for 8 out of 16 boards on my bench . The self-boot pin goes high immediately after  power-up by local micro processor. ADAU1442 is the only I2C slave on the I2C bus, the rest of the I2C slave chip sets are on separate I2C bus.  The pull up resistors on SCL & SDA bus are 10K. EEPROM write protection is disabled by a pull down.

The EEPROM data looks valid in the read/write window for boards with self-boot failure. I shall probe /reset & self-boot pin to investigate the timing.

The ADAU1442 process audio when it is in debug mode (connected to Sigma studio through JTAG).

Any idea what is going on?? why the self-boot is flaky?