I have been flooded with questions asking how to root the new Jelly Bean OTA update for the Droid Bionic! Unfortunately there is no method for rooting Jelly Bean if you have already installed the OTA update. The only way that you can root is to manually protect root with VooDoo OTA RootKeeper. If you are still on ICS then you are in luck.
1.) Be sure to update your SU binary
2.)Install Voodoo OTA RootKeeper
3.)Press Protect Root (DO NOT Press Temporarily Unroot!)
4.)Install JB OTA
5.)Open OTA RootKeeper and Restore Root
If you have SafeStrap or BootStrap installed you will have to uninstall in order for the OTA to take.