According to official information, Droid 4 does not have an option to calibrate the screen. Using custom tools is not recommended because it may brick your phone. If the screen does not respond, please take the phone to a local phone repair service or to your warranty service.
Official statement:
The Droid 4 by Motorola uses capacitive multi-touch technology. Screen calibration is not supported at this time. - Verizon Wireless
