Did you notice the AMD Zen3 RDRAND "bug"? Somehow, a hardware circuit consisting of a different odd number of noise diodes for each bit, and a hardware implementation of a hash function for whitening, always generated the number 0xFFFFFFFF (-1). I took it as a signal from a technical person at AMD, letting us all know that it wasn't really hardcoded and there was some kind of backddoor to disable it. And I'm glad linux never relied upon RDRAND.