Re: Secureboot in ATECC608A - Compatible devices?
Any device with I2C can use the secure boot. Best to use Harmony for I2C and the SHA256 hash performed in your custom bootloader. You will need to write your own set of state engines for communicating with the ATECC608A, in order to provision it with a public key during manufacturing, or else use the Microchip Trust suite. Then, during boot all you do is SHA256 hash your application code (using Harmony) write the hash and the (Factory) signed hash to the ATECC608A, and wait for the ATECC to verify whether the 32 byte hash is correct. If it is correct then jump to the application code.
All that code takes some space, and my latest bootloader takes up 25% of the program flash for a 795MX device, although it performs functions besides secure boot.