In this post, we'll show you how you can find the UDID of your iPhone, iPad and iPod touch for iOS 5 activation. It is mandatory that the UDID of your device be registered with the Apple Developer Program before you can install beta firmware on it. Since iOS 5 is in beta right now, you need to register the device UDID, and here's how you can find it out.
Step 1: Plug in your iPhone, iPad or iPod touch to the computer and launch iTunes.
Step 2: Now once in iTunes, select your device by clicking on its name in the left sidebar. Then, hover your mouse to where it says Serial Number and click on it.
You'll notice that Serial Number disappears, and in its place, appears Identifier (UDID) followed by a long string of numbers and alphabets. This is your device UDID. Copy it down very carefully.
That's it! This is your device UDID which you must get registered before you install beta firmware on your iPhone, iPad or iPod touch. If you do not get your UDID registered, your device will run the beta firmware, however, it will not be able to sync with iTunes, until and unless you get it registered, or you install the public version of the iOS firmware on your device.
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