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Hitachi based ECU, how ROM specific are download procedures?

PostPosted: Tue Jul 03, 2007 6:00 am
by Ziggyrama
Hey guys,
I own a Nissan 350Z and I used to tune my WRX which I sold not too long ago. I did some poking around and it turns out that Z's ECU is based on a Hitachi chipset, very similar to the EVO. I am not certain how close they are as far as architecture is concerned. I tried to to crack the ECU open to visually examine it for clues but it's well sealed in the metal case and I can only pry it open slightly without damaging something. I don't want to force the issue as I fear I will break something vital and give myself a very expensive bill.

So, my question is, since openECU supports EVOs, and since the Z ECU is reportedly very similar, how ECu specific are the download procedures? I'm a programmer so I understand the complexities of computer software. I guess I am trying to gauge the chances of me being able to plug the cable in and download the ROM off an ECU that may have the same instruction set as a one that is already supported. Is the ROM download car maker protocol specific? Subaru has SSM, Mitsu has their own. Is ecuFlash dependent on them specifically?

I know the ROM contents, I am on my own there but getting the ROM out is the first step at maybe cracking this thing. I do have access to IDA Pro so I am capable of disassembling the ROM to some extent.

Any info you guys can provide will be much appreciated.

PostPosted: Wed Jul 04, 2007 3:31 pm
by radsdau
If the processor is the same / similar to EVO, then there is a good chance the kernel code that Colby has written will work.

The big question though is getting the kernel into the micro and convincing it to run. This will depend on the bootloading scheme Nissan have implemented. As you've seen Mitsu and Subaru both use entirely different methods of making this happen. This is very likely to be equally as different.

Short of using BDM to suck the brains out of the micro (which you may not be able to do), it will probably be a matter of mimicing something that works already, if that exists.