...you must right down your adjustments settings. I am talking about the settings that are tweakable via software outside of flashing. An example is the Bosch Motronic's settings that can be changed with Revo's Lemmiwinks or that other software, the name of which escapes me now... Unisettings from Unitronic, that's it.

When the ECU goes into this mode where it spits out its flashed .bin file, you will notice that the check engine light turns off. Also, you will notice that you can no longer connect to the ECU after the operation has completed (whether successfully or not). You have to cycle the ignition to get the ECU to be back in its standard operational mode. When that hapens, I am certain that those settings are lost, whether you read a flash or write a flash in the ECU.

Here is my experience with the B5 S4. I had raised the idle RPM by about 60-80 RPM on top of the 800 RPM. This because the car is much smoother at idle. This may not be necessary for most cars, but I have RS4 motor mounts, which are solid and very stiff, and it gets really cold in the Winter where I live. Before the engine bay warms up and the motor mounts warm up, the car idles fine but the vibration is felt in the cabin. Raising the idle by a slight amount helps. (A side-note: do not raise the idle by too much because the engine will not be able to settle at the prescribed idle and it will cycle -- ask me how I know.) After having read my flash using the NefMoto software that Tony built, I noticed that my idle was back to 800 RPM. I read the settings with Lemmiwinks and they were all back to the defaults.

Now you know.

I, too, was surprised. again, this is speculation on my end but I think the ECu goes into a special mode when reading is done , and this is deduced from my observations described above. When that happens, Lemmi settings are lost. Most likely other adaption channels are lost.

One more emperical and highly non-scientific piece of evidence. I noticed that for the 50 miles that I drove my S4 in 30F to 40F weather it seems to be putting out a bit more steam than usual. I guess the adaption data was lost and the car is re-learning itself.

My CH-box from my 2001.5 A4 1.8T Avant seems to have retained its Lemmiwink settings fro mme having read the stock flash from it.