In a nutshell, Unrevoked Forever changes the security level on your phone — allowing you to load custom software to any partition on your phone. That means you can load custom boot, recovery, splashl, and hboot images. And because it sets the security flag at a very deep level, the change is (sort of) permanent. The Unrevoked team promises that even if your wireless carrier sends out an “unrootable” over the air update, you should still be able to reflash a custom recovery image if you already have Unrevoked Forever installed.
That said, using this software will void your warranty. And if you don’t know what you’re doing, I’d advise staying away altogether — or at least spending a lot of time reading up on custom ROM hacks. That’s because once you change the security flag and start loading unofficial software there’s a much better chance that something could go wrong and you could end up with a phone that won’t boot at all.
Right now Unrevoked Forever is only available for the HTC Droid Incredible and HTC Evo 4G. You can find more details, warnings, and instructions at Unrevoked.com.
via Android Central