Clearing adaptations before flashing new program

[ATB88]

I've read in a few places that it's advised to clear adaptations before flashing the DME to a new program version so that it can start fresh and adapt properly to the new programming without having to start from adaptations that may have been reinforced by aspects of the old program.

This makes sense, but I guess I'm wondering why the old adaptations stick around after you've flashed the DME to a new binary? My guess is that adaptations and details like that live somewhere else in the DME's memory than where the program binary lives, so, flashing doesn't affect it? Or does flashing wipe out adaptations and the above advice is irrelevant?

[terra]

This makes sense, but I guess I'm wondering why the old adaptations stick around after you've flashed the DME to a new binary? My guess is that adaptations and details like that live somewhere else in the DME's memory than where the program binary lives, so, flashing doesn't affect it?

This would be correct. Strictly speaking you don't have to delete the adaptions before flashing the DME - you can do it after (in fact, after might be better).

[TheEnd]

There's usually two memory sections in most ECUs, the flash and the eeprom. Flash is fast to read, but reprogramming is done in chunks. EEproms are usually tiny, not as fast but their benefit is you can read and write individual bytes.

The flash part will usually stay the same, whatever you write into it will still be there in a year. The eeprom however is like a notepad and that is where stuff like fault codes, the EWS rolling codes, adaptations etc will be stored. These will stay the same during programming.

Clearing adaptations before or after will have the same result.

BMW always do the adaption clearing afterwards, and in some cases, afterwards is needed.
For example, on an MS43, there is the C_CONF_CATS variable which tells the ECU what the catalytic converter set up is. The default inmost cases is "we have 2 pre cat, and 2 post cat"
That can be edited "you have 2 precats, and if you see any more, you have have post cat too", so if you do program to precat lambda only, you'd want the post cat lambdas unplugged, and clear the adaptation afterwards (under variant adaptation)

So all in all, afterwards is perfect, before programming can sometimes be a little pointless.