The iPhone 3GS was released in June 2009 as an updated version of the iPhone 3G. The 3GS features a faster processor, better camera and faster downloading speeds than the original 3G, but retains the 3G body shape, allowing it to use 3G accessories without an adaptor. There are 32 individual screws found in the 3GS with several different lengths. All screws are Philips-headed and are size "#00." A size #00 Phillips-head screwdriver, a suction cup and a plastic spudger are needed to open the 3GS and to remove and replace certain parts.
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.
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.
There are five 2.3mm Phillips #00 screws with partial threads securing the logic board to the rear panel; two 2.3mm screws with full threads securing the logic board and camera near the top of the 3GS; and one 2.9mm screw hidden under the "Do not remove" sticker near the bottom of the phone.
Two 1.5mm screws are found on either side of the dock connector circuit board, and one 2.4mm screw is found near the ribbon cable labelled "4."
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.
There are four screws securing the headphone jack to the phone casing. Three 1.8mm screws secure the headphone jack and GPS antenna to the back panel and one 3.8mm screw us found in the plastic loop near the top of the phone.
A single screw attaches the black plastic spacer moulding to the outside case near the top of the phone.
Two 1.9mm screws secure the vibration mechanism to the back casing.