Read the MCU ID from a Bosch EDC17/ME17, Simos or MD/MG EEPROM dump.
Some immo-off operations (especially newer-generation ECUs) need the MCU ID. You cannot change it — it is OTP (One Time Programmable). You can usually see it on the flasher's main screen or in the file name while reading the ECU.
It looks like 400XXX…0000, typically 16 or 32 hexadecimal characters. The value may also be encrypted inside the dump, and some devices report it incorrectly.