Try a forced restore:
1. Start iTunes. Go to prefs -> Syncing -> Disable automatic syncing.
2. Plug iPhone to a USB connected directly to the computer (no external hubs).
3. Simultaneously *hold down the home and sleep/wake buttons until the screen goes blank, then continue to press the home button alone* until iTunes sees the phone in restore mode.
4. Restore the phone and set up as a "New iPhone" - don't restore from a backup.
5. Before manually synching - check the phone functions.
6. Instead of synching everything, go to the applications page and add each one at a time.
7. If you still get the corrupt firmware message, there is a hardware defect and you need to take it to the Apple store genius.
Message was edited by: modular747