For iPhone 3GS,iPhone 4,iPod touch 4G and iPad1,Please refer to following steps to set Device Scanning Mode for your phone:
1. Connect your iPhone to computer, and then run the application in Recover from iOS Device
2. Hold your device, then click Start button in application.
3. Hold Power and Home buttons on your iPhone at the same time for exact 10 seconds.
4. Release Power button. Keep holding Home button.