iphone 4g 4.0.1 if cellular data not visable
 

Step 1. Run Cydia app go to sources and add this source: cydia.pushfix.info
Step 2. Now go to search and type Carrier Reset fix. Select Carrie Reset fix and install it.
Step 3. Eject the SIM when installation completes and re-insert it.
Step 4. Now head over to Settings>General>About> hope you will see the correct carrier bundle.