Have you even found the documentation around things like ACPI? It's kinda coupled with UEFI these days I think, and hell, I'm not even sure of the hardware boa

Have you even found the documentation around things like ACPI? It's kinda coupled with UEFI these days I think, and hell, I'm not even sure of the hardware boards/revisions aircraft makers are using these days... Are they still on BIOS? Or old-as-sin linux/RTOS kernels/microcontrollers? Point being, when you start talking about high QA systems, where the Quality is non-negotiable (you will have everything documented and tested); barring exec/managerial malfeasance in preventing that work from being done, you reach for the same simple things over and over again since it takes a hell of a lot of work to actually characterize and certify a thing to the requisite level of reliability/operating conditions. Testing ain't free, ya know.