two smoked 04 USDM STi ecus so far :(

[Freon]

The rom dumps are tiny! The biggest is 1MB, which I wouldn't consider large at all. And that is uncompressed.

I really don't think you should flash a whole downloaded ROM, period. I don't have a whole lot of faith in "off-the-shelf" pre tuned maps. I don't think you should flash even a "difference file" some unknown person made.

I think few vendors have enough testing in them, and even then you may have poor results. People even complain about Cobb's base maps and sometimes have poor results. Do you think someone else can do better? How much testing is in these files? Does the person who made the file even have that car? Where is a running log?

[chuckdez]

The rom dumps are tiny! The biggest is 1MB, which I wouldn't consider large at all.

My real point was saving the difference from the base and the modified is smaller and efficient.

I really don't think you should flash a whole downloaded ROM, period.

My understanding is OpenECU doesn't rewrite the entire ROM only areas modified. Which wouldn't be much if you changed a fuel or timing map. The byte positions don't move since you are not increasing or decreasing the size of the tables.

I don't have a whole lot of faith in "off-the-shelf" pre tuned maps.

That's fine by you, however atleast three-quarters of the market just wants plug-n-play. Do they even know or care that their vehicle could put out more power if properly tuned, more than likely not.


The feature I was suggesting is.. Saving only the modified values from the tables, not the entire ROM. The ability to read this file and apply those values to your vehicles actual ROM. There is some variables you would have to account for like somone trying to apply WRX to FXT. However I'm not trying to design it here, just adding a suggestion.

[radsdau]

I think what you're proposing is smart for Subarus. The issue is not size of code, but it's that people are reflashing other people's ROMs into their cars and ending up with dead ECUs.
As Colby said, you should really start with the stock ROM read from your ECU, and edit that, not downloading random images and flashing them.

But what would be even better is if the base ROM was never actually modified; any changes would be written to a 'difference' file as suggested. Then tuning a ROM with ECU Flash would require opening 2 files: 1. the stock ROM image for your car; 2. the difference file.

When a reflash is done, the 2 are 'merged', not affecting any security settings or the like.

(The 'difference file' could even describe where the stock ROM image file is.)

It also allows checking if the files are compatible before editing and burning are done.


I bags not writing the code.

[Freon]

My real point was saving the difference from the base and the modified is smaller and efficient.

I understand. But 1MB is still small in today's terms. Why bother creating a construct for "difference" files. Waste of time to save negligible bandwidth.

My understanding is OpenECU doesn't rewrite the entire ROM only areas modified. Which wouldn't be much if you changed a fuel or timing map. The byte positions don't move since you are not increasing or decreasing the size of the tables.

Yes that is correct, but I wasn't getting into the specifics of the flashing procedure itself. My point is you probably shouldn't download a whole ROM someone else made and flash it to your car (ignoring the fine points, just considering ECUflash as a "black box"). The other person could've mislabeled it, you may mistakenly flash the wrong revision or model, or mistakenly believe your ECU and some ROM you downloaded is a close enough model or revision to work, etc. I think this has happened before and resulted in a dead ECU. I'm not going to reread this whole thread, but I think that is a possibility for the OP of this entire thread.

The feature I was suggesting is.. Saving only the modified values from the tables, not the entire ROM. The ability to read this file and apply those values to your vehicles actual ROM. There is some variables you would have to account for like somone trying to apply WRX to FXT. However I'm not trying to design it here, just adding a suggestion.

There may be a slight use for this, but the size of the maps can change from year to year. The timing map might be 15x18 one year, and 16x17 another, creating a heck of a translation problem. Also, since many many maps interact together to create the final tuning values, you may end up screwing things up bad if you only flash some of the changes. You can never get them all since a great majority of the thousands of maps and values are unknown. It just isn't practical.

I think it is far more practical to look at a running log or discussion of what someone has done to there map to fit their needs and apply those techniques to your car.

[S54fan]

Can I ask if anyone has fried a Subaru ECU from simply modifying and reflashing their original ECU image?

When I used to tune 99/00 Subaru ECUs with Ecutek tools I always had to keep a supply of spare ECUs (two types) because every now and again the programming would fail for some reason, and it wasn't recoverable. Because the Prodrive Performance Packs had new ECUs and because of users going to standalones it was relatively easy to buy up old standard ECUs.

However, there are now so many different ECU types that whilst I'm very happy with the tuning aspect, I do not want to leave my friend's car immobilised when I do a quick tweak to his ECU, but I'd prefer not to have to purchase a spare ECU to just cover a single Subaru programming as a favour for a friend.

So how sure are we that these faults are user errors either in method or the ROM image they're flashing?

[tato01]

I have a MY05 and had the same problem, reflased and then the car wont run.
Tried to download again with no luck, no communication with the ECU.
Doing several possibilities to bring back it alive, I found that using the TARI software with the battery disconnected, open the entire program to the point of reflashing “OK button”, connect the battery at that point and it start to reflash.
I have to do the reflash procedure several times since it only reflash partially.
When I complete the reflash the car started.
Hope this can help

[tato01]

Found another thing, use jump cables with another car and the read/write problems are gone; I tried all day finding why I couldn’t read the dam ECU.

[WJM]

Any end user solutions? Or did I miss something?