Since the Core Rulebook came out, I thought that the Firewall can never exceed the System value, because it's a software attribute und thus somehow, like rated programs, connected to System. But Unwired destroyed my blissful ignorance: Security cameras, smartguns and other nodes' Firewalls exceed their Responses and Systems.

Was I wrong? Is there no connection? Should I go home and think about my life? And stop selling those killer-sticks?

Your confusion is understandable, but you have been wrong. Programs are limited by System, Firewall isn´t.

Firewalls are partly hardware based today. the good ones anyway. Is that maybe a solution?

They handled it in a most fucked-up way. Like Ryu said, even though Firewall is listed as a program, it's really not. It's just a software-based device attribute and has no bearing on your system's performance or limitations at all. You have a System 1/Response 1/Signal 1/Firewall 6 device with no reprecussions at all. Well, not because of the Firewall 6 at any rate.

I'm honestly not even sure why they decided to list it that way at all rather than simply keep it as an attribute.

I, too, wondered about that. Now I think of it as a piece of firmware. But this makes it more cheap to secure important parts of your PAN like expensive drones or implants.

Firewall is a program. It's just neither a Common Use nor a Hacking Program nor an Agent, and thus isn't limited by System.