Just a couple days ago, an RUU (version 2.10.605.1) was leaked for the HTC Thunderbolt. Well the gifts keep coming, and over at XDA, a user has leaked another RUU. The newest version is 2.11.605.0, and it is only pointing at the still imminent release of Gingerbread for all you extremely patient Thunderbolt owners.
If you flash, you will lose root, and it will wipe your device. If you want to save root, wait for a little while until a developer can work on it, and package it up properly. Be safe.
Update: Rooted version available here.