External Screws

• There are two external screws located on the bottom of the iPhone 3GS. The screws are found on either side of the dock connector and can be removed with a size #00 Phillips-head screwdriver.
  
  

Screen

• There are six screws found on the display assembly that includes the LCD screen and glass touchscreen. There are three Phillips #00-sized screws found on the left side of the display assembly, two along the right side, and one near the top.
  
  

Logic Board

• There are five 2.3 mm Phillips #00 screws with partial threads securing the logic board to the rear panel; two 2.3 mm screws with full threads securing the logic board and camera near the top of the 3GS; and one 2.9 mm screw hidden under the "Do not remove" sticker near the bottom of the phone.
  
  

Dock Connector

• Two 1.5 mm screws are found on either side of the dock connector circuit board, and one 2.4 mm screw is found near the ribbon cable labeled "4."
  
  

External Buttons

• There are two Phillips screws attaching the on/off switch to the top of the phone. Four screws attach the volume and vibrate on/off switch to the case. The screw closet to the top of the phone is slightly longer than the other three.
  
  

Headphone jack

• There are four screws securing the headphone jack to the phone casing. Three 1.8 mm screws secure the headphone jack and GPS antenna to the back panel and one 3.8 mm screw us found in the plastic loop near the top of the phone.
  
  

Back Spacer

• A single screw attaches the black plastic spacer molding to the outside case near the top of the phone.
  
  

Vibrator

• Two 1.9 mm screws secure the vibration mechanism to the back casing.