RomRaider

I have been using RR and ECU flash for a few years on my 07 Subaru and a couple other 05 and 08 Subaru. I was under the impression that if the stock rom was flashed back to the ECU after a modified rom was previously flashed there would be no way to identify that the ECU had been tampered with. Recently I came across a thread about the pro/cons of OS tuning vs. AP, specifically that the AP when unmarried from the vehicle, restores the original CID AND makes the fact that it was ever modified undetectable while OS reflash such as with RR or OpenECU would change the CID.

I ask this because I have told some others, most importantly the peoples vehicles who I had edited the roms/flashed the ECU, that if the dealer had to log the ECU or for any reason hook up to it with a computer that it would not show any evidence of modification. (assuming the exact stock map that was saved from that exact ECU before the first reflash was restored via flashing it back on) If I am mistaken, I would like to know so i dont continue to look like a jackass.

Is the ROM ID and the CID the same thing?

I did 3 searches with CID as a keyword and found several threads where CID is talked about but none as the subject of discussion or with evidence to support either yes/no about the CID changing with OS reflash.

Thanks!

There's three IDs plus a two checksums. With any reflash whether off-the-shelf or open source the CAL IDs and ECU ID can remain the same as in the OEM ROM. There's no need to change it really. What will change are the CVNs (calibration verification numbers) as they are values derived from a calculation of bytes across two address ranges in the ROM. These ranges always cover the logic and the calibration maps. So changing just one byte of an OEM ROM and flashing it back will result in all IDs being equal but the CVNs will calculate to different values than the published values by the manufacture. That's the tell-tale sign that the ROM has been changed.

You can't fool the dealer when the CVNs are different than what they expect. But this should have no bearing on logging as long as no one changed the IDs.

Flashing back the OEM ROM should restore everything, even the CVNs. There has been recent discussion that a dealer can still detect the number of flashes an ECU has had over time.

Provided those flashes were made by a dealer equipment ...

what dschultz said

if there is a write counter in these ecu's, they will know because they would be able to read it. there could be a separate rom checksum function somewhere hidden but then we should also be able to find it/read it since it should have an address, unless it's a piece of hardware which we should also be able to hack into.

Next time I have a chat with my dealership guy I'll ask. He hasn't mentioned anything to me yet about it (It's his car I've just done the def request for) but we'll see.

Thanks for the quick and informative responses everyone.

A related question: Does the dealer automatically check the CVN anytime they do a read/write or is it something that they usually don't pay attention to unless they suspect the rom has been modified? Maybe their software automatically flags a CVN that is not "correct"?

Thanks again.

If anyone would like to share any threads or articles about this topic that would answer a lot of these questions and get into the details of this topic I would be interested in reading.

I guess that depends on what the dealer suspects is wrong with the car and/or is there a recall out to change the software and do a reflash. For this they would definitely query all the values. They may even ignore them and just overwrite the modded ROM putting the ECU back to what the factory suggests.
The CID is available via the OBD mode 9 read PID 4
The CVN's are available via the OBD mode 9 read PID 6

I appreciate all the info. You all have been very helpful, as usual.

Cheers!

Can we hard code the output to match the original calculated values?

OBD\SSM responce maybe hard coded.
There is a but.
Code and calibrations ( except bootloader code ) maybe uploaded thru SSM commands and CVN and CID maybe recalculated.

That's not a bad idea for getting around aftermarket flash detection!

That won't be a feature you'll see in RomRaider. We are not about fooling the dealer or manufacturer that you have changed your car and wish to hide the evidence. That's not what RomRaider and this community is about.

Yes I agree it does cross an ethical boundary. I'm not going there.