My '07 M3 has a retrofitted CIC, and that took close to a minute I would say for the update.
But in my wife's '11 X3 it was lot quicker more like 30 sec. There are no difference to the respective updates. The screen messages are the same.
I think if the USB must be formatted with FAT, not NTFS. for the car to see and read the update file.
E92 M3 2007 - ///PE with Test Pipes and BPM Stage II; CF Interior & Splitters; CIC with Connected Drive