1.From your phone’s dialer dial ##634#. This will launch the Diagnostics screen, which is just another dialing screen.
2.Once there, input 40*047#3
3.Now that you have entered the above-mentioned code, you will see the Confirmation flash as shown in the screenshot (taken on Omnia 7) above. Tap OK.
4.As said in the confirmation message, this will reboot your device.