This is really scary!

I'm only a software (not hardware) engineer, but if I were to design such a system, I would ensure that there is absolutely no connection between the plane's network and any network that passengers have access to. I don't trust software firewalls (there's always a way around them) or other "proprietary technical solutions" that haven't stood the test of time.

If Boeing really wants to ensure that the passenger Internet service doesn't access the maintenance data or the navigation system "under
any circumstance," then they should keep the systems separate!