[9dev]

> I'm not sure what you mean when you say John Deere was cheating the system.

Instead of selling tractors with more powerful, but limited motors, they should have sold tractors with less powerful motors and no screw. There is no need to do any of this in software. They were purposefully avoiding the regulation by telling farmers, "do not loosen that screw, or you'll break the law, wink-wink!"

[Manuel_D]

I'm no mechanical engineer, but can't any motor be run with greater power if the fuel mixture settings are remapped? Is it possible to design a motor that runs at 25 horsepower at leaner emissions-compliant settings, but can't run at higher power if a user changes the fueling settings to a richer mixture? I'm skeptical if it's even possible to design an engine that runs at 25 horsepower when complying with emissions requirements, but can't be tuned to run at higher power if users have the ability to change fuel settings.

> They were purposefully avoiding the regulation by telling farmers, "do not loosen that screw, or you'll break the law, wink-wink!"

They were? The whole point of John Deere locking down the firmware was to prevent this metaphorical loosening of the screw. It looks more like John Deere invested heavily in preventing modification of its hardware, much to the chagrin of farmers who wanted to cheat emissions.

It's more like: every engine has a metaphorical screw that can change the fuel mixture - this is inherent to combustion engines. John Deere made it really difficult or impossible to change that screw. Now farmers regained the ability to change that screw under the guise of repair.

[bumby]

I think your general point is reasonable, but far too centered on emissions. There are other reasons to limit modifications beyond just emissions. As an example, most turbocharged vehicles are de-tuned to a much lower psi of boost. The can run at much higher HP but also reduce emissions (depending on what type of emissions you're concerned with. Sometimes decreasing one type corresponds to an increase in another). They often force consumers to a lower psi rating for reliability reasons. So should a user be forced into higher reliability by a manufacturer? That seems like a much less clear answer than being forced into lower emissions.