2nd reflash, is this normal?

Developer topics relating to software that reflashes or modifes ECU code and data

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2nd reflash, is this normal?

Postby agkq62 » Wed May 11, 2011 11:59 pm

I am very new to working on ecu flashing so feeling my way in very carefully.

When I did my first test write and reflash the progess bar stop at about 50% for quite a long time (the log file was updating) and the whole thing took about three or four minutes.

When I did a second test write and reflash the progress bar moved across to 100% very quickly and the reflash was over in about 30 secs.

Is this normal please?

I have read the new flash and it seems to have gone in ok.

Thanks.
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Re: 2nd reflash, is this normal?

Postby agkq62 » Thu May 12, 2011 12:31 am

Should have added, first flash was a modded dbw table and about 6 disabled DTC, second flash was a modded dbw table.

Just want to put my mind a rest that I haven't done anything stupid.

Thanks.
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Re: 2nd reflash, is this normal?

Postby radsdau » Thu May 12, 2011 4:22 pm

Not sure what car you have, but I don't know of any that should take 3-4 minutes, unless it's a slow PC. I presume a 1Mb DBW non-CAN ROM. The length of time is most certainly affected by the changes in the ROM; it only flashes the blocks that have changed.
The largest flash block is the last one, which contains the checksum table. This should change if there are changes in the ROM elsewhere, requiring a flash. But if you use ROMRaider it nullifies the checksum table at the end of the ROM (so checksums are no long checked at boot time), so this block should only have to be flashed once. This flash block is large so will take a fair amount of time. Any later changes not involving this block may only affect flash blocks which are far smaller, therefore flashing quickly.
Does that make sense?
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Re: 2nd reflash, is this normal?

Postby agkq62 » Fri May 13, 2011 3:23 am

Thanks for the reply. sorry I forgot the vehicle details, you were right, 06 2.5 Forester Turbo.

With my limited knowledge your explanation makes sense, and yes I am using RomRaider to edit.

Could the fact that RR nullifies the checksum table cause a problem?

Would I be safer to use EcuFlash to alter the tables.

Thanks again.
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Re: 2nd reflash, is this normal?

Postby radsdau » Sun May 15, 2011 3:51 pm

It's not really a problem, but yes, using ROMRaider would cause that symptom.
It's neither here nor there if you use RR or ECUFlash. Personally I like to have a valid checksum table and not bypass the safety system, but with these ECUs it doesn't matter anyway; if there's a flash corruption or checksum mismatch, the code still runs, it just pulls a diagnostic code.
Your choice. RR is fine.
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Re: 2nd reflash, is this normal?

Postby agkq62 » Mon May 16, 2011 12:07 pm

Thanks again, but I'm afraid you have prompted another stupid question.

"if there's a flash corruption or checksum mismatch, the code still runs, it just pulls a diagnostic code." Am I right in assuming the diagnostic code is in the EcuFlash log and not the CEL on the vehicle?
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Re: 2nd reflash, is this normal?

Postby radsdau » Mon May 16, 2011 4:18 pm

No problem.
I mean an OBDII trouble code (CEL/MIL on). It would probably cause the car to revert to 'limp home' mode.
Flash corruption is unlikely, especially during the reflash process; ECUFlash performs some good CRC checking before committing each block to flash. A corrupt ROM would normally only happen in the ROM editing, which again is unlikely unless there is an error in the XML defs, or you are hacking the ROM yourself. XMLs are fairly mature these days, in most part.
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Re: 2nd reflash, is this normal?

Postby agkq62 » Tue May 17, 2011 11:49 pm

Thought I had that situation at my last reflash, then realised I hadn't uncoupled the green connector :oops:
If I did get a flashing CEL on restart I would have to reflash with a know good hex file?

Just nice to know what to do if things do go wrong.

Thanks again.
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Re: 2nd reflash, is this normal?

Postby radsdau » Wed May 18, 2011 4:05 pm

AFAIK the only thing that causes a flashing MIL is test mode (or crashed flash- ECU would probably be bricked in this case). That's not to say there are other scenarios I don't know about.
But yes, revert to a known good ROM if possible, if you can't make the flashing MIL go away.
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Re: 2nd reflash, is this normal?

Postby agkq62 » Wed May 18, 2011 11:38 pm

Thanks again, you can have some peace now. I think I'm sorted. :)
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