Have an Epic 4G? Then, this guide by XDA member kennethpenn may be something for you. It helps you to flash the new Android 2.2.1 ROM using a detailed guide, the necessary downloads and instructions. You will lose root by flashing this, so keep that in mind. After the update, you can use the one-click root utility again to gain root.
Make sure you select the right packages according to the firmware you are currently using, there are different packages for 2.1 and 2.2.
Continue on to the thread to try it out!