How to downgrade iPhone iOS 4 to OS 3.1.3

Apple's iOS 4 looks great, has loads of new features, works just fine on a 3GS. But it's turned our iPhone 3Gs into expensive ornaments: it made them - and the 3Gs of everyone we know - so slow they were barely useable.

The good news is that you can fix it; the bad news is that you need to dump iOS 4 and it takes ages. Here's how to roll back iPhone OS to 3.13.

Disclaimer: Future Publishing Limited provides the information for this project in good faith and makes no representations as to its completeness or accuracy. Individuals carrying out the instructions in this project do so at their own risk.

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