- Download the required files from here
- Extract them to a folder
- Install latest Motorola drivers (Download)
- Enable USB debugging mode in phone setting
- Connect your Droid 4 to PC
- Execute “RUN.BAT” from the extracted files
- You're good to go.
Credit to Dan Rosenberg for this root exploit.
Be sure to check out this thread aswell! - Droid 4 Utility Pre-Release [WINDOWS]