chrisw

iTrader: (2)

that is really dangerous and I don't recommend it unless you absolutely know what you are doing. like mchuang said, the code and data segments can change, who knows what else changes.

You can do this on a limited basis, but only between the same ECU hardware. I did this when I first started with ECUflashing to get rid of a unknown p0300 patched rom. Knowing what I know now, I don't think I would do this again without fully researching the problem first.

JohnBradley

iTrader: (30)

Same series of car (USDM/JDM/EDM) with the same year grouping will interchange as far as my personal experimenting has determined.

I have run 13,14, and 15 with no issue on IX's. Every VIII Rom that is common between the 03/04 and experimented with what 05 will work on earlier cars. A large portion of the addresses are even the same between the VIII and IX for things like OBDII some others. Even EDM to USDM have somethings in common not that they will interchange (that I know of).

Wiring harness differences (pinouts and hardware interface) are the only thing that complicate the interspecie crossing with the Evo. I fail to see how it is "dangerous", though I will admit it might not be preferable. You can always flash it back.

JB

codgi

iTrader: (22)

The funny thing I've also noticed with my marginal time dealing with software and hardware in general is that "close enough" usually ends up producing a bunch of phantom bugs/issues that are hard to find reproes for and even harder to debug. While I have no doubt what you said is above is true John I think if people just stick to the specific rom for their particular ECU its probably best.

JohnBradley

iTrader: (30)

I agree Codgi, 99.5% of the stuff I do or try isnt needed by the average enthusiast. Its just that sometimes things are needed so you experiment and see what happens. Like injector scaling for the IX used to be ONLY the 15 rom. So if you had a 13/14 and wanted bigger injectors you had no choice...until I figured out you could make the scaling function work with the 13/14 as well.

I dont see the 2 byte load as anything different, but thats me. If their ROM doesnt have the support, then flashing to a different ROM to get it is about the same. It would be nice if I was smarter and could figure it out and give a better answer, I agree.

chrisw

iTrader: (2)

you have to realize that car companies save money by using common hardware that is easily configured for a particular car model.

for instance, people have found in the ECU software that it has the capability to handle 6 injectors, not 4.

Depending on how the software is configured, can support multiple different vehicles with the same ECU. This is common practice in the industry.

But sutble items can change, like pin outs on the ECU, or other hardware (sensors, and other inputs) depending on the year, model, and where that model was sold ( USDM vs JDM).

You can switch software, but you really need to be careful to match up the version of software you want, with the ECU hardware you want to run the ROM on.