Got it !!!
The solution :
Retrieve the file
generalPersistencyData_DiagnosticSWTController as described in this thread :
https://www.e90post.com/forums/showthread.php?t=1154524
The fact is that this file
generalPersistencyData_DiagnosticSWTController has plenty of "
0x01 0x01 0x00 0x1d" fragments. Firsts ones don't have the right VIN but 1234567 VIN instead. So, you need to search for the first fragment which contains the right VIN corresponding to your car and extract it as described in the link. With this valid 1b file, you'll get the right fsc code
FYI : the script (copy_scr.sh) contained in 1b.zip file, attached to this thread , seems to pick up the first fragment which is obviously the wrong one.
One more thing ; i was able to update my map by using 3 usb keys...
