How to Check iPhone Firmware Version (Field Test Mode)

1. Turn on the phone and slide to unlock the keypad. iPhone screen should show that only emergency calls is allowed.
2. Enter the following key sequence: *3001#12345#* and then finish by pressing Call button. This will enter field test mode of iPhone.
3. Tap on Versions.
4. The firmware revision information of iPhone installed out of the box will be shown on LCD screen. The following guide will match the firmware revision to the firmware version. 03.12.06_G – firmware version 1.0.0
   03.14.08_G – firmware version 1.0.1 or 1.02
   04.01.13_G – firmware version 1.1.1
   04.02.04_G – firmware version 1.1.1