If your PRL version is 60686 or earlier, select Menu => Settings => System updates => Update PRL. After updating the PRL you should also update the Profile. Once you have rooted your phone, do not accept any other software updates from Sprint.
If your Android version is 2.3.5, you will need to use the HTC Dev tool to unlock the bootloader on your EVO by following these instructions:
http://forums.androidcentral.com/ht...26-guide-rooting-phone-hboot-2-18-0001-a.html. HTC Dev requires that you first have the following utilities installed on your computer: Android SDK
Android SDK | Android Developers, Java Runtime Environment
java.com: Java + You, and HTC Sync
HTC Help Center (only needed for Windows computers). HTC Dev then guides you through a 10 step process to generate a token which you must submit in order to receive a binary file which is required to unlock the bootloader.
If your Android version is 2.3.3 or earlier, you can use Revolutionary to unlock the bootloader and gain root access by following the directions here:
http://forums.androidcentral.com/ht...oot-evo-4g-gingerbread-via-revolutionary.html.
Once you have unlocked the bootloader, you will need to install a custom recovery. Although Revolutionary does install clockworkmod recovery, I recommend installing Amon Ra v2.3 by following the method described at
[Recovery] [09-Feb-2011] RA-supersonic-v2.3 - xda-developers.
If you were able to use Revolutionary to unlock the bootloader and install SuperUser, your EVO is fully rooted and ready for use with the stock ROM already installed on the phone; however, you can install the custom ROM of your choice by following the method demonstrated in this You Tube video:
How to Flash a ROM on the HTC Evo 4G.flv - YouTube. Be sure you make a Nandroid backup within recovery before you wipe the phone and install a custom ROM or kernel so that you have the option of reverting back to your current configuration in case the phone fails to start properly or becomes unstable during normal usage.