AMD stripped [Transparent Secure Memory Encryption] from its consumer CPUs

You don’t have to use cellular on a phone, you can use it like a computer.

https://xcancel.com/GrapheneOS/search?f=tweets&q=cellular&since=&until=&min_faves=

The cellular radio for every smartphone supported by GrapheneOS is an isolated and unprivileged peripheral component. GrapheneOS doesn’t sit on top of the cellular radio and it doesn’t control the SoC either. It’s very similar to how the Wi-Fi/Bluetooth radio is integrated.

The CPU in every modern computer is a massively complex closed source component. The reason people are talking about AMD PSP or cellular radios is because they’ve been misled by companies scamming people who claim they’ve changed things while actually making devices less secure.

The idea that cellular radios are unique in being closed source is wrong itself. Every mainstream CPU, GPU and many other components used in computers are closed source. Open source firmware and especially hardware isn’t nearly as successful as higher level software has been.