A few hours ago, via his Twitter account, iH8sn0w announced that a new version of Sn0wbreeze is coming that will allow users to preserve the baseband wile upgrading to firmware 4.2.1.
Those who do not know about Snowbreeze, Snowbreeze is a tool to create custom firmware without upgrading the firmware. But the new “Baseband Preservation Mode” is different from the old version as it allows you to restore your iDevice firmware to iOS 4.2.1 without upgrading its baseband, it will not jailbreak or unlock the device.
In this way, even users of the iPhone 3G and iPhone 4 aliens can update the firmware 4.2.1 and enjoy untethered jailbreak. There is no release date announced yet, we will inform as soon we know more, stay tuned with us !