Update: unrEVOked has released a new version of Forever that allows you to turn S-Off and On – so go ahead, be rooted forever.
UnrEVOked has made rooting incredibly easy. Now they’ve also made it permanent. With unrEVOked’s “Forever” tool you can have root, well, forever. It works by setting the phone so “S-Off” – removing the safety check for update files stored on the SD card. This means any zip file that is saved to the SD card can be applied as an “update” to the phone. If an OTA update removes root from the phone, no problem, simply apply the Clockworkmod Recovery ROM – the phone won’t check to see if it’s a signed update and it will be installed – and you have root again!
The downside is that, well, this is forever. Right now there is no way to set the phone back to “S-On.” This means that, if you use unrEVOked Forever, you’ll be breaking your warranty and be left with no way of going back. All-in-all though, it’s a great step forward.