If you want to keep your jailbreak and unlock, you better not update to this latest firmware now until and unless official new jailbreak and unlock tools are available for download. You would need to have iTunes 10.1 in order to upgrade to iOS 4.2. All you need to do is to connect your iPhone, iPad or iPod touch with your computer via USB and start iTunes 10.1. You should now see a message as shown below.
Simply click on “Download and Install” button to get on to the new firmware.
Download iOS 4.2 [Direct Download Links]
Below are the direct download links (official) for iOS 4.2 firmware.
Download iOS 4.2 for iPhone 3G Download iOS 4.2 for iPhone 3GS Download iOS 4.2 for iPhone 4 Download iOS 4.2 for iPod touch 2G Download iOS 4.2 for iPod touch 3G Download iOS 4.2 for iPod touch 4G Download iOS 4.2 for iPad 3G and Wi-Fi
