Read first before going to the GUIDE step by step!

This is my guide on how to achieve S-OFF on an unrooted, NAND-locked device running the latest (4.67.651.1){4.67.651.3)(5.07.651.1) Latest OTA HBOOT version (2.18) with Android Version 2.3.5. 

The method involves using HTCDev.com to unlock the Bootloader of the device (which this guide will not cover, as there are procedures on the HTCDev site for that).

This guide will cover what to do after your Bootloader is "unlocked" by that process, in order to roll back your HBOOT to a non-watermarked version that can be rooted with unrevoked.

The rooting process with unrevoked will also not be covered in this thread, as it is well-documented.

Files you'll need

Armon_RA-Recovery - USED IN STEP 3 (there are 3 different versions you can use - I recommend this one):

Recovery click DOWNLOAD don't forget to check the
md5: 219FE492872E2BFAD57C16545BA340CE

Superuser 3.07 - USED IN STEP 4 DOWNLOAD

md5: fc462fa0630379edbe10006b1d19d9b1)

flash_image binary - USED IN STEP 9 DOWNLOAD 
md5: 97B64A4C8CB22E39F79062402D26A126)

Misc/MTD Partition IMG file from Engineering build-IN STEP 9 DOWNLOAD 

md5: 830C28C64A02023CB806306326070F7B)

3.70 Froyo ROM with 2.10 HBOOT
md5: 7056D42812AA5DF03FCC8DDDC2B64E85
USED IN STEP 10
1.Download-PC36IMG.zip |2. Mirror DownLoad(FileFactory) | 3.Mirror (4shared)

Fastboot Files to extract inside C:/android instead trying to install SDK, I had narrow it down just the ones you need. DOWNLOAD

HTC Driver3.0.0.007.exe DOWNLOAD





"IMPORTANT NOTE!" Image files like flash_image and MTD_image have the contents unzip or extract first and movethem outside the folder and place them on the ROOT on the SD. Command will not see files if inside folders or still in zip formats. Read more important notes below before clicking on the "Instructions Below."

Instructions with IMAGES click [HERE!!]

IMPORTANT NOTES:

• If all you want to do is root and be able to install custom ROMs, then you do NOT NEED THIS GUIDE! HTC's unlocker will allow you to do that by installing a custom recovery.This guide is NOT for beginners. If you don't know WHY you want to be S-OFF, then you probably don't need to be. This is for advanced users, or those who are still under warranty and need to send their phone for repairs after using the HTCDev unlock process.
• This guide assumes that you've completed the unlocking process from HTCDev.com, which means you've also downloaded fastboot/adb to a local folder on your computer. That will be the same folder from which you will be running the commands listed in this thread.
• The Superuser file is a flashable zip, which means it must NOT be extracted after downloading! After download is complete, copy to /sdcard as-is, so that it can be flashed in recovery.
• In order to flash recovery in fastboot, the recovery.img file from the zip file needs to be in the same folder as the fastboot.exe.
• The flash_image binary and the mtd-eng.img can be placed on the root of the /sdcard prior to starting the S-OFF process.
• The PC36IMG.zip should NOT be placed on the SD card until the step (10) where it is used. If you have it on the card, it will cause delays in loading fastboot on the device.

• If the bootloader doesn't recognize the PC36IMG.zip, and you used Windows Explorer to rename the PC36IMG file, make sure you didn't add an extra ".zip" to the end of the file name. Most people hide file extensions, so that can happen without you even realizing it (especially if you see that it's already recognized as a "ZIP" file). If you still have issues after checking that, the only other reason it wouldn't work is a corrupt or faulty SD card. If you can try a different card, see if the PC36IMG file works on it.
• If you'd prefer to root/NAND unlock using Revolutionary, you can substitute the Froyo ROM file (in Step 10) with a Gingerbread ROM file (any version up to 4.54). The latest version unlockable with Revolutionary can be found HERE!

THIS A VIDEO GUIDE OF THAT WILL HELP FURTHER IN DETAIL.