I know a few people who have issues with updating their iOS version. Especially those with the iPhone 3G who report of their device literally dying when they update to the iOS 4.1, making update to the latest version a huge pain. Of course they still want the look and feel of the iOS 4.1 and it is exactly why we have got Firmware Changer.
The tool enables you to change the device’s firmware version with an easy to use GUI. The first relief it gives you is that it removes that continuous update your iOS notification whenever your plug your iPhone, iPod Touch or the iPad. Reports also state that it would also enable the installation of apps on the older iOS, though the running of the application is not a guarantee. The tool is available for free at the ModMyi repository at Cydia.