" Sorry to put a damper on the parade but the flash tuning capability of the new turbo M models is greatly overstated. A couple of days ago results were posted of a flash tuned S55 inline-6 which is the turbocharged M motor
featured under the hood of the F80 M3 and F82 M4. It is true that this car was flashed but after seeing the article BimmerBoost was contacted by a tuner who wanted to set the record straight on what is actually going on.
Nobody at the moment has real control of any modern ECU used in the turbo BMW's. This includes the F30 models, F10, F12/F13, F82, F80, and so on. The tricore ECU's in these cars have not been cracked. So what exactly is going on?
The tuners claiming the ability to flash are all using the same trick but they are not uploading their own custom tuned software. They are essentially flashing the same files that originate internally from BMW. Some of these files are just press files. Oh, you did not know BMW uses different software on cars they let the press test? Well, namely with the F10 M5 and F12/F13 M6 they do.
Why? The BMW press software will allow a higher margin for a CEL (check engine light). That means you will not see any of those nasty reviews saying the cars went into limp mode. This among other things like traction control changes or higher boost itself. Some tuners have even been using the BMW Competition Package software which is not real flash tuning. It is just uploading BMW's own file.
If anyone needs proof of this ask for a custom dyno tune for your F10 M5 or F80 M3. It is not going to happen, at least not yet. Tuners can play with the bootloader but if they modify outside of certain parameters the checksum fails. If it fails, the software will not flash. "