Today a user reported to us that he is not able to update his iPhone to the latest iOS 4.3.3 because iTunes was giving error. The issue was still unknown until the user at Modmyi reported the same issue.
None of my devices with updates available (of the three, none are currently jailbroken, these are iPads used for business) are able to update currently – I get a new error today “this device is not eligible for this build.” iTunes also on the iPad screen says “this device has an update available.” I do not currently have a custom gs.apple.com host set.
First iTunes connect to Apple Server then it recognizes your iDevice and then send the Firmware Activation to the Apple server which was down for the moment.
But this issue seems to appearing to few users. Few hours back i just updated my iPad 1 to iOS 4.3.3 on Orignal and Custom Firmware and it worked flawlessly.the server might be due to the load on the server because today Untethered Jailbreak was out and every might be onto Updating their iDevcie to the latest one and Jailbreaking it.