The big fallacy about radios in faraday cages being invulnerable to EMP is sort of hypothetical. Completely isolated, yes possibly. However, it is not a ‘radio’ if it can’t pick up anything (i.e., without using a transmission line to an antenna). It is here through this path that it becomes vulnerable and requires a lot more thought about mode and method of protection.
But wouldn’t it mean that since avionics don’t need to act as radio they can be shielded with faraday cages and transistors are still better than vacuum tubes?