>In fact, it's quite common.

Really? How have you defined common? Where is that data from? I can't imagine anything more than a tiny fraction of car owners are doing this. Most people are not hacking their cars, building Raspberry Pi controllers for their toilets, or have any desire whatsoever to side load an app on their iPhone. The HN community is not representative of the overall population.

It's common enough that there's a legitimate industry around that and a lot of auto-tuning shops will do it on request. In most cases though it's just editing the built-in data tables rather than completely replacing the firmware, and it's often done for engine performance reasons rather than bypassing safety features.

And possibly blowing the cars’ mileage and emissions limits which were defined by regulation and would make the car illegal to drive if measured…

Mechanics do it often, as do people who work on their cars. It isn't the Hacker News segment that is doing it, but the people who work on cars for a living or for fun.

And you’re free to jailbreak your phone. It’s not illegal. No ones going to arrest you.

But no one says the car manufacturers are required to make a car where you can flash the ECU. There’s just no reason for them to block it. If someone came up with a way to steal your car by tricking your into running an app that flashed your ECU then you can bet Ford would disable it pretty quickly.

> But no one says the car manufacturers are required to make a car where you can flash the ECU. There’s just no reason for them to block it.

Sure there is… if they are providing warranty on the vehicle then they should definitely block ECU mods, as a customer could flash original firmware back after causing damage.

And I imagine you can easily make an engine over-rev or overheat with a modded ECU, perhaps to the point of causing a fire or other catastrophe.