[delfinom]

But do you trust the processor? Which can also be backdoored internally to start rewriting instructions on the fly?

[fsflover]

You use different CPUs and compare the result. Also, you can try this: https://www.crowdsupply.com/sutajio-kosagi/precursor

This is called "security through compartmentalization", i.e., you don't trust one single entity. The only approach that works.