Originally Posted by mahanddeem
Is there a risk of loosing the "IMEI" if I downgrade ???? I heard about that and I don't wanna that happen to me !!
Considering that you'll be using official update files and the stock recovery mode, the risk of anything going wrong should be very low. Losing the IMEI number is definitely on the very low end of things going wrong.
Best Case Scenario: The 2.3.6 "update" installs successfully and you don't even have to wipe your data.
Most Likely Scenario: The 2.3.6 "update" installs successfully but you get a boot loop and will have to wipe your data and install it again. Then everything will be working.
Other Most Likely Scenario: The 2.3.6 "update" will refuse to install. You'll be stuck on 4.0.3. You could still try wiping your data to see if it helps your issues though (there's a good chance it will).
Worst Case Scenario: Something unusual goes wrong during the install process and bricks the phone. Simply installing the update won't brick your phone. It takes something actually going wrong, like the battery randomly falling out (or running out of juice, so make sure you have a good charge left).