If you want to ensure the SoC is not backdoored, your only option is Precursor, which can make a fairly solid claim that silicon backdoors for FPGAs are infeasi

If you want to ensure the SoC is not backdoored, your only option is Precursor, which can make a fairly solid claim that silicon backdoors for FPGAs are infeasible in the general case. https://www.crowdsupply.com/sutajio-kosagi/precursor https://www.crowdsupply.com/sutajio-kosagi/precursor If you're willing to trust that the silicon isn't secretly backdoored in some ridiculous invisible way, well, unlike Intel, the M1 does not have any hyper-privileged proprietary firmware by all indications, and that proprietary firmware which does exist is plaintext and analyzable (and not privileged to scan memory), so I have a much easier time trusting these machines than a random x86 PC (all-privileged SMM supervisor and ME/PSP) or Android phone (all-privileged TrustZone supervisor).