Since the launch of AMD Ryzen, a small piece of hardware that handles basic memory initialization as well as many security functions has been the center of some controversy. Called the Platform Security Processor (the "PSP" for short) it is essentially an arm core with complete access to the entire system. Its actions can be considered "above root" level and are for the most part invisible to the OS. It is similar in this regard to Intel's Management Engine, but is in some ways even more powerful.

Why is this a bad thing? Well, let's play a theoretical. What happens if a bug is discovered in the PSP, and malware takes control of it? How would you remove it (Answer: you couldn't). How would you know you needed to remove it? (answer, unless it made itself obvious, you also wouldn't). This scenario is obviously not a good one, and is a concern for many who asked AMD to open-source the PSPs code for general community auditing.