I did some experiments with the ATECC608A version in the M5Core2 AWS kit. Using the aforementioned libraries with I2C address 0x35 I can make it wake up and read information from it. However for me it did not show up using an I2C scan, even after waking it.

From the full datasheet I understand that 0x35 is the default I2C address which can be modified exactly once to something different. Looks like that has not yet happened with the ATECC608A in my M5Core2 AWS kit.

In contrast the M5Stack ID Unit uses the ATECC608B version for which I was not able to find the full datasheet (it looks like it requires an NDA). I assume that either the same mechanism exists regarding I2C address for the B version and 0x60 is the default or it already has been modified from 0x35 to 0x60 by M5Stack. (I don't have the M5Stack ID Unit so I cannot confirm whether it uses 0x35 or 0x60.)

Thanks
Felix

looking through the documentation I think the ATECC608 needs to be woken up first before it reacts to anything like an I2C scan.

I haven't found an example for M5Stick, but since it is also part of the M5Core2 AWS package maybe this example can help you.

Then there is the example given on the product page.

Thanks
Felix