I want this because right now I use camera cards to boot. The key needs to be wired directly to the processor and be the first and only entry point. Instantaneous boot is what I want, not resuming from hibernation but "instant on" of the full system.

> What are you booting?

I am booting Linux, BSD, custom systems, lightweight bootstrap programs that do a specific task like diagnostics.

> On which architecture / machine?

Agnostic / various. For instance, instantaneously booting / running only on GPU(s).