People repair stuff they own all the time, and if they do a bad job of it, they are liable for any damages caused. All that's really needed here is some clear way to indicate that this factory-issued X has been modified by the owner to be an X1 model. End of story.

We can't continue down this path of people developing software and somehow in the process picking up vast quantities of physical goods that buyers think they actually own. Not only is it evil, it's nonsensical from the viewpoint of the average informed person. The only reason it's worked as long as it has is that most people aren't informed enough about it. Tractors might be the straw that breaks the camel's back on this issue. People don't think much about the inner workings of their phones, but Joe Farmer fixing his tractor is a concept most folks don't have difficulty getting their head around.

Let's not. These farmers don't want to change the software. They only want to fix their hardware.

And because of the close tightness with the software, they can't.

People repair and modify their cars every day - and these are driven on public roads among other drivers and pedestrians. Farm equipment is operated on private property and among workers who are mostly aware of the risks. In the end, if the vehicle is unsafe, the driver is responsible.

JD is a knife manufacturer who puts countermeasures to prohibit knives owners from sharpening second side of the blade (among others things). Because it can be dangerous.