I don't think it would be that hard. There's RISC-V SBCs out there which the schematics are open for. I don't think it's correct to assume absolutely everything

I don't think it would be that hard. There's RISC-V SBCs out there which the schematics are open for. I don't think it's correct to assume absolutely everything out there is backdoored/compromised. That would be an very difficult undertaking and word would get out. NSA target their attacks very finely.