Here's your clarification... You can WRITE over obd 2 but you CAN NOT READ your original file from it with out removing the chip and use a chip burner
Hope that clears it up for you
Technically that is right. But I have found that some parts of serial eeprom & flash eeprom content are uploaded to RAM´s MCU (87C196). For example serial eeprom is located at RAM address $0C250 - $0C350. MCU Factory Test Code is located at address $02012-$02080H. Also data content of the flash eeprom (MAPs) seems to me that are uploaded too, but I am not totally sure about it.
As ME7 does and some code, procedures, maps & values are mounted in RAM for it process. The difference is that factory code in ME7 have procedures for it interaction, but in older Motronic are not available or at least are not public known. Maybe I am wrong, but that are my impressions playing with my ECUs.