How to Determine if iPhone is On Firmware version 1.1.1 or Older 1.0.x
If your aim is simply to check and determine whether your iPhone is running on newer version 1.1.1 or older version 1.0.x of firmware, the fastest and easiest method is by holding down the
Power (Sleep/Wake) and
Home button until iPhone enters restore mode by displaying one of the following image on screen -
sync cable and iTunes logo or
yellow triangle.


The sync cable and itunes logo is the new firmware 1.1.1. restore screen, while the yellow triangle is the old firmware 1.0.2 restore screen. However, this may change in future firmware upgrade.
How to Check iPhone Firmware Version (Field Test Mode)- Turn on the phone and slide to unlock the keypad. iPhone screen should show that only emergency calls is allowed.
- Enter the following key sequence: *3001#12345#* and then finish by pressing Call button. This will enter field test mode of iPhone.
- Tap on Versions.
- 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.