HP TC4400 - Manual (Page 139)

5–56 Maintenance and Service Guide
Removal and Replacement Procedures
2. Disconnect the Bluetooth module cable 1 from the system
board and remove the cable.
3. Remove the four Torx8 T8M2.0×5.0 screws 1 that secure the
system board to the computer.
Removing the System Board Screws, Part 1