[EVO 4G Android Development] benholtz:
This Is a How-to that I created after learning the process with help from the freenode #HTC-EVO IRC Channel and on XDA's forums.

I AM NOT RESPONSIBLE FOR ANYTHING THAT HAPPENS FROM THESE INSTRUCTIONS, THEY WORKED FOR ME ON 2 DIFFERENT EVO's WITH NO ISSUES.

Start with 2.1 Stock and skip step 1 if you are already rooted with unrevoked3.

1. Root with Unrevoked3. (unrevoked.com)

2. Install Unrevoked Forever. (See the Unrevoked Site for instructions unrevoked.com or use mine)

A. Transfer unrevoked forever.zip to sd card and shut down the phone.

B. Reboot your phone into recovery mode. You can do this by removing your phone's battery, holding down the VOLUME DOWN button, and inserting the battery; at the menu, press VOLUME DOWN to highlight recovery, then press POWER to select it.

C. select the "install zip from sdcard" then "choose zip from sdcard" select the unrevoked-forever.zip and install.

D. Reboot Phone.

E. After your phone starts, shut down phone and start back into HBOOT. You can do this by removing your phone's battery, holding down the VOLUME DOWN button, and inserting the battery;

F. Verify the First line on this screen says "S-OFF"

3. Create Stock Recovery installer and flash to Stock Recovery

A. go to Menu>Settings>System Updates>HTC Software Updates, click "Check Now".

B. Click OK to download the Update. Note, this will not install the update... yet.

C. Once the Download is complete, Choose "Install Later".

D. Use a program called "Root Explorer" or another file browser to transfer the file (/cache/OTA_Supersonic_3.26.651.6-1.47.651.1_releasexxxxxxxxxxxx.zip) to the SD Card.

E. From your computer create stock recovery installer by extracting the OTA zip onto your computer, extract the zip inside of the OTA zip called firmware.zip. Then add the files android-info.txt and recovery.img from the firmware.zip to a zip file called PC36IMG.zip.

F. Put this file onto the SD Card.

G. Reboot your phone into HBOOT. You can do this by removing your phone's battery, holding down the VOLUME DOWN button, and inserting the battery;

H. it will detect the update and ask if you want to update and press VOLUME UP to do it. It will then say update complete and ask if you want to restart the device.

I. press VOLUME UP to restart the device.

4. Install the OTA Update

A. Once the device boots up you can now install the OTA Update, go to Menu>Settings>System Updates>HTC Software Updates.

B. Click "Check Now" and Click OK to download the Update. (if needed).

C. Once the Download is complete, Choose "Install Now".

D. Now let it install the updates and reboot (10-20 mins).

5.Flash to a Custom Recovery to allow rooting.

A. Once your phone has finished loading up with the new update, you will probably want to root your phone with a recovery such as "ClockworkMod".

B. Place the file on your SDcard to replace the one you used before (make a backup of the previous one if you wish to replace the recovery back to stock after rooting).

C. Reboot your phone into HBOOT. You can do this by removing your phone's battery, holding down the VOLUME DOWN button, and inserting the battery;

D. it will detect the update and ask if you want to update and press VOLUME UP to do it. It will then say update complete and ask if you want to restart the device.

E. press VOLUME UP to do so.

6. Root/Install Superuser.

A. Now you will want to "root" your phone by using Superuser 2.3.1.

B. you will want to be sure to use the the Eclair/Froyo version su-2.3.1-ef-signed.zip. (Search XDA for the file)

C. Copy this file to your SD card.

D. Reboot your phone into recovery mode. You can do this by removing your phone's battery, holding down the VOLUME DOWN button, and inserting the battery; at the menu, press VOLUME DOWN to highlight recovery, then press POWER to select it.

E. Select the "install zip from sdcard" then "choose zip from sdcard" select the su-2.3.1-ef-signed.zip and install.

F. Reboot Phone.

7. (Optional) Flash back to stock recovery with the zip as in step 2 be sure to remove.

8. Remove PC36IMG.zip from your SD Card.

9. Enjoy!

10. Any problems should be taken to the #HTC-EVO IRC channel on Freenode.