It wouldn't even have to be that. There's enough specialized US data communication and GPS microchips in there that any one of them could be compromised. There's more than enough history of this, people not willing to consider it are part of a bubble: https://en.wikipedia.org/wiki/Hardware_backdoor#History

"The 'kill switch' in the F-35 is more than just a rumour," Joachim Schranzhofer, the head of communications at German defense company Hensoldt informed the local media outlet Bild. "But it's much easier to use the mission planning system - then the plane stays on the ground."

I'll take the word of the head of communication at a German defense company that has actually vetted the systems over armchair commenters any day.

Then there's the possibility of backdoors to access mission critical data by deliberately compromising their encryption: https://www.atlasobscura.com/articles/a-brief-history-of-the-nsa-attempting-to-insert-backdoors-into-encrypted-data

Then there's the chasm between "complete technical schematics" being available and actually being able to produce said equipment without resorting to a US controlled supply line. It's not just firmware, if they cut off access to maintenance supplies, you aren't going to have it easier than Russia is having it with their sanctions, it's still going to take its toll on your supply line.

Like VW firmware that knew when emissions were being tested. You can hide it in there for sure

They aren't idiots. You don't set up your entire military to be bricked by a hack.

You know, I did actually try to head off this line of reasoning by pointing out that a) we have the entire technical package, and b) there are no extraneous communications going into or out of a stealth fighter, of any kind.

Like, buddy, I really did try to give you all the pieces. I was like "Do I need to spoon feed ALL the conclusions? No, they're a smart enough person, they'll figure it out."

No, that is not a remotely practical idea. First, no one is just accepting whatever random signals they get sent while flying a stealth fighter, or indeed any kind of fighter. Electronic warfare has been a thing for as long as integrated circuits have, we're not idiots.

But more importantly, any capability you put in firmware has to ultimately talk to the hardware. There has to be an actual lever to pull, somewhere. It's not magic. And firmware isn't like the software on your phone; it's not a general purpose computer. You can't just run an app. There's no kernel to allocate resources. Every single component on the F-35 has its own firmware, that runs that component, and the ability for those components to communicate with each other is strictly limited to what can actually be communicated at a hardware level. At some point any kind of "killswitch" would ultimately require hardware capabilities that would be obvious to anyone with the technical package, because those are exactly the kind of cascade failures that you would want to make impossible in the event that there was, say, an entirely normal, non-malicious bug in the firmware. You build these things to be failure proof, which makes it very hard to then sneak in ways to deliberately make them fail.

And I think the part that, above all else, you really, really need to wrap your head around is that we're not idiots. Canada is an extremely technically capable nation. We didn't buy this thing without experts reading the specs. And those same specs were read by experts from every other country in NATO, and none of them believe this kill switch myth is real.

So basically your theory stands on the assertion that you - John or Jane Internet User from Fucking Wherever - have, with zero access to any of the technical data, spotted a danger that all of the experts from every country in NATO missed, throughout the entire thirty plus years of the F-35 program, through around five different US administrations, all of them working in concert to conceal these capabilities, with zero complaint from Lockheed Martin, one of their biggest defence contractors, who don't even mind that discovery of this capability would destroy their international sales forever.

That's flat earth levels of self-delusion.

Also the idea that there is no possible way to sabotage these planes via technology is comical.

Now this is a classic example of making a completely different claim than the person you're responding to, then countering that, and acting as if this means you've countered any of their claims. Peak bad faith argument. Well done.