Interesting. There's probably some open-source software on GitHub that could be used.

I forgot I asked "Open source software for automotive ECUs?" on softwarerecs.stackexchange.com in 2017. It hasn't received any answers…

@Geremia - Something to remember which I didn't state is, you can most likely use the ELM327 for doing what you're suggesting, but the real question is: Should you? My suggestion is, not at all. Reason being is, the ELM327 has to be open to receive electronic interference. Because of this, if you should happen along any, you can brick your ECU, which means ... it's dead. Not much you can do but use it as a paperweight at that point.

I'm familiar with putting custom firmware on routers and bricking them. There's usually a way to restore the factory firmware.

@Geremia - When I say "brick", I mean brick. As in: no longer works.

I'm not too familiar with flashing VINs, but that wouldn't seem to require rewriting and flashing the firmware. I could be wrong.

@geremia - It seems it is doable, but not fun. Bottom line, any interruption in the flashing event can cause it to be bricked. Recovery is not easy, so why risk the biscuit in the first place. Removing all chances of bricking the PCM in the first place will make life a lot easier. Trying to flash a PCM through a Bluetooth connection would seem very risky to me. This would be a risk I personally would not want to take, especially if I was doing this on a customer's car.

@Geremia - Basically, yes.

You have to pull the entire "tune", change the VIN, then write it back into the PCM.

By "pull it off", I mean, you copy what is on the PCM out onto your computer. Once it is downloaded you have a bin file, which you need to translate so it becomes human readable. Then you can find the VIN in the tune and make the changes.

@Martin - Hello!