I know this thread is from 4 months ago, but it was on first page of google search. So I will post the tutorial here in case it helps anyone.
no adb shell, no terminal, no paid apps.
Put your phone in airplane mode
Download the free app "Sqlite" (https://market.android.com/details?i...=search_result
) from market (need superuser)
Go down and find "preferred_network_mode"
Go right and find its value (mine was 7). Change to 0.
Tap menu button and close the Sqlite.
Ps: I recommend you to delete the widget!
Note: Im not an expert in android root. I have a Galaxy S i9000. Use at your own risk (my dream's to write this phrase!!)