The best way to do it would make all persistent storage in the device modular so that the storage device can be attached to a device that isn't booting from it which can thereby verify its contents.
Notice also that remote attestation doesn't enable that. The device can never do that itself since if it was compromised it would just display "attestation passed" on the screen without actually doing it.
Notice also that remote attestation doesn't enable that. The device can never do that itself since if it was compromised it would just display "attestation passed" on the screen without actually doing it.