Let's not forget you need to verify by hand the electrical characteristics & functionality of every logic chip you use to build that homebrew CPU, because the supply chain of basic logic chips is already known to be infected (primarily a QA issue, but clearly a potential vector)
Don't forget the power company. They can cause "spurious" bit flips by momentarily dropping the voltage at just the right instant. Best to use a battery made from potatoes you've grown yourself.
You also need to ensure either the device, or the location you operate the device is rad-hardened. We cannot rule out the possibility that They can control the phases of the sun and introduce errors to your circuit at-will with solar flares.
True, though I suspect you are going to be doing that already since you will undoubtedly fuck up your homebrew CPU in novel ways many times while building it, and spend many hours debugging each piece of it. ;)
