I have just finished the Denim update for my Lumia 925 successfully except that I can't change the connection speed to 3G because this option in Cellular+SIM setting is not activated. I did the following trying to solve the problem:
1. I tried to soft reset the phone
2. I replaced the SIM with another one for another carrier.
but the problem still exists.
What should I do ? Is the problem from the phone or a bug in the new update?