1. Plug your iPhone into a Mac via USB and turn it on.
2. Go to Applications > Utilities > System Profiler.app
3. In System Profiler in the left pane, Go to Hardware > USB.
4. In the Right pane, Go to USB Hight-Speed Bus > Click iPhone
4. The Serial Number = UDID
2. Go to Applications > Utilities > System Profiler.app
3. In System Profiler in the left pane, Go to Hardware > USB.
4. In the Right pane, Go to USB Hight-Speed Bus > Click iPhone
4. The Serial Number = UDID