Comment by somerandomqaguy

Authorized software means authorized for that car's VIN number. Basically it's the same issue with parts in Apple products that are serial number locked.

If for instance if you damaged a headlamp, and then went to an authorized BMW dealer, bought the correct brand new OEM BMW head lamp assembly from the parts department of an authorized BMW dealer, and followed the replacement procedure to the letter in the BMW service website... it won't work. The headlamp assembly is not authorized to talk to the rest of the car even though it's OEM, untampered, with stock firmware.

The headlamp has to be reprogrammed with the correct VIN number in order for the rest of the ECU's in that particular car to recognize it as authorized.