1: Put spare cluster to car and ignition on, make virgin, turn off ignition.
2: Put back original cluster to car and ignition on, read Immo Data, eeprom and read mileage. Don't turn off ignition.
3: Let ignition stays on and take out original cluster and put spare cluster to car, write immo data, eeprom and recalibrate mileage.
4: Now you can reset cluster .
5: Turn off ignition and wait 30 second, now you can fire up car.