Earlier quoted context omitted.
Unfortunately, Torvalds supported tivoization: https://lkml.org/lkml/2007/6/13/289
Because anti-tivoization doesn’t make sense in a software license. Imagine you make a smart toaster, and you make it entirely out of open source software. You release all the changes you made too, complying fully with the spirit of open source. People could take your software, buy some parts and make their own OSS toasters, everything’s great. But for safety reasons, since the software controls when the toaster pops,…
And, you know, it works great. It's simple to operate and (so far!) has been completely reliable.
I can hack on it in any way that I want to. There's no aspect of it that seeks to prevent that kind of activity at all.
What would I hack it to do instead? Who knows, but I can think of a couple of things. Maybe instead of having some modes where the elements are in series, I want them in parallel instead so the combination operates at higher power. Maybe I want to bypass the thermostat with an SSR and use my own control logic so I can ramp the temperature on my own accord and finally achieve the holy grail of a perfect slice of toast, and make that a repeatable task.
Whatever it is, it won't stand in my way of doing it -- regardless of how potentially safe or unsafe that hack may be.
There are countless examples of similar toaster ovens in the world that anyone else can hack on if they're motivated to do so, and very similar 3-knob Black & Decker toaster ovens are still sold in stores today.
And yet despite the profoundly-accessible hackability of these potentially-dangerous cooking devices (they didn't even bother to weld the cover on or use pentalobular screws, much less utilize one-way cryptographic coding!), they seem fine. They're accepted in the marketplace and by safety testing facilities like Underwriters Laboratories, who seem satisfied with where the bar for safety is placed.
Why would a toaster oven (or indeed, just a pop-up toaster) that instead used electronic controls need the bar for safety to be placed at a different height?