Understanding the Causes of UEFI/EFI Lockout

Hi,

So I am new to this arena and am trying to understand how the EFI lockout thing works. My particular machine is Macbook Air Mid 2012 (version 5,2), but I think this pertains to many older Macs. My understanding is that there is a hardware chip on the the Logic board of most Mac computers that verifies that a given processor matches the logic board, and is authentic/original. Does the check go any further, say, to verifying whether an OS or the SSD matches its original logic board or CPU? The implication being that if you took an SSD with an OS on it, and installed it in another computer, would you get locked out? What if you take a different logic board and put it into another computer, do you get locked out?

In general, what are the types of replacements or modifications to the computer that trigger the EFI lockout? With a locked out machine, is there a way of restoring it (say, by installing an SSD with a clean OS on it)? I am looking at logic board replacement for my Air and need to make sure I buy components that won't turn out to be bricks when I install them.

Thanks so much for your input!

D