iOS delta updates are only delta through the device, not iTunes
Along with the new iPad announcement, we saw the release of iOS 5.1. However, with iOS 5, one of the major improvements was further updates to the software are delta updates – only the parts of the OS code that have changed are downloaded and installed. Yet I was unaware that these delta updates only occur if you update from the device, not iTunes. If you decide to use iTunes to get the latest and greatest iteration of Cupertino’s software, you better be prepared for a longer wait, and a bigger bite into your quota. For both my iPhone 4s and my iPad 1, the software update option through the device was a 200Mb download, but through iTunes, was 700Mb. So if you haven’t updated your iDevice yet, you may want to keep this in the back of your mind!
