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:
Instructions:
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.
Code:
adb push misc.img /data/local/
adb push busybox /data/local/
adb shell chmod 777 /data/local/busybox
To gain root and flash misc.img:
Code:
adb shell
su
/data/local/busybox md5sum /data/local/misc.img
If the output is anything other than "c88dd947eb3b36eec90503a3525ae0de," stop and start over again.
Now let’s write misc.img:
Code:
dd if=/data/local/misc.img of=/dev/block/mmcblk0p17
Rename "PG05IMG_Mecha_VERIZON_WWE_1.12.605.6_Radio_1.16.0 0.0223r_NV_8k_1.41_9k_1.64_
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.
Code:
adb reboot bootloader
You’re done – your phone should now be stock, S-ON.