Note: This is applicable only if you have a 1.1.1 firmware with 04.12.03_G baseband

Step A: In order to connect your phone to the computer,

1. Go to installer from your iphone
2. From the bottom of your phone press Uninstall 
3. Select "ITunes Detect Fix", then press reinstall
4. Now restart your iphone

After you restart the phone, plugin to the computer. Now your computer should detect the phone but
with no signal. Now do the necessary music, movie files transfer to iphone and follow the steps below
to get the signal back.

Step B: In order to get the signal back

1. Go to installer from your iphone
2. From the bottom of your phone press Uninstall
3. Select "No Service Fix 1.1.1", then press reinstall.
4. Now restart your phone.

At this point you should have gotten the signal on your phone.

Note: Step A and  Step B must be repeated everytime you want to connect your phone to the computer.