Rooted Users (Non - Root Users scroll down below):
PG05IMG_MR1_no_hboot.zip - c64b4367086fff4f51ec3d5d766a0456
Bootloader (FLASH THIS LAST) FLASHING THIS WITHOUT SUCESSFULLY FLASHING THE ABOVE FILE WILL CAUSE A SECURITY WARNING
abda920f3e159fb05c00d8c54a5b8768 - PG05IMG_hboot_1.4.0000.zip
Flash the above PG05IMG_MR1_no_hboot.zip to restore everything to stock + OTA BUT still will have the s-off bootloader.
Rename PG05IMG_MR1_no_hboot.zip as PG05IMG.zip, and flash through hboot (like in the root guide).
To restore the bootloader, rename PG05IMG_hboot_1.4.0000.zip as PG05IMG.zip and flash through the bootloader. DO NOT FLASH THIS unless you are absolutely sure PG05IMG_MR1_no_hboot.zip flashed to your device, without issue.
Now you are done, enjoy. If you screwed up, and got a security warning contact me, don't stress. Then again, don't screw up.
Non root users wanting to return to 1.12.605.6 (Stock, pre OTA) can continue below:
NOT FOR ROOT USERS
Taken from AndroidPolice: [Tutorial] How To "Un-Root" The HTC ThunderBolt And Return It To Stock. Please check the site out.
One of the most popular questions about rooting the ThunderBolt is how to undo the process and return to stock, which renews your eligibility for customer support. Well, here you go:
Please read the whole tutorial first, and pay attention to every detail. Note that your battery needs to be charged to at least 40% at the beginning of the process, and remember to check the MD5 sums of all downloaded files before diving in. As always, neither Android Police nor Team AndIRC are responsible for any damage this may cause to your phone, and, needless to say, returning to stock means you will no longer be able to use root apps like ShootMe and Titanium Backup.
First, download the following files:
Stock firmware (MD5 sum: 7141f5620f6128af77d50587e341f4b0)
exploits.zip (MD5 sum: 3b359efd76aac456ba7fb0d6972de3af)
Next, push exploits.zip and misc.img.
adb push misc.img /data/local/ adb push busybox /data/local/ adb shell chmod 777 /data/local/busybox
adb shell su /data/local/busybox md5sum /data/local/misc.img
Now let’s write misc.img:
dd if=/data/local/misc.img of=/dev/block/mmcblk0p17
release_174685_signed.zip" to "PG05IMG.zip" before placing it on your SD card.
Finally, reboot into bootloader mode by entering the following command. Allow the stock firmware to flash.
adb reboot bootloader