[floatboth]

Yeah, AMD went in the exact opposite direction of

> an “external ME” would be just fine running without a CPU socketed in at all

and made Ryzen a nearly-SoC, EPYC an actual SoC (no chipset at all required AFAIK). (To be fair Intel did integrate many things onto the die as well..)

https://fuse.wikichip.org/news/1177/amds-zen-cpu-complex-cac... seems to confirm that SMUs are on-die at least on EPYC.

> Interestingly the Chromebook EC firmware is open source

And even the Google Security Chip is included under that. You can't run a customized GSC firmware on a production device unless you have Google's keys, but you can look — and hopefully maybe reproduce the build?