OTA problems. Please help!!

[GTRDEALER]

I have tried installing the OTA update three times. After waiting forever to download the update when it tries to install it starts and then i get a picture of a phone with a red triangle and an exclamation point. I called Verizon they had me do a master reset of the phone and had me try again. Same problem again. So when I called back they told me that it was because I have rooted my phone in the past even though it wasnt rooted anymore was the reason why the update didn't work. Any way to install this update? Or do I need to root this phone again?

 

[yodatom10]

U can do it manually follow the link
[Exclusive Download] Leaked 1.70.605.0 Update For The HTC Thunderbolt (No, It's Not Gingerbread)