If you're a mechanics freak and let your curiosity get the better of you by dismantling and re-assembling all appliances around you, you probably must have had similar thoughts about your iPhone. If you haven't opened it up yet, it may be because you don't want to take the chance of ruining your beloved, expensive gadget! Here is all you need to know about how to open your iPhone in a systematic manner and ensure no harm is inflicted upon your smartphone. Though it closely resembles an iPhone 4 from the outside, an iPhone 4S packs quite a few hardware features that are very different from the former. Among other hardware features, it has a tamper-proof feature that consists of the two pentalobe screws on the bottom. Unscrewing these is no mean task and can be accomplished only by a 5-star screwdriver. Apart from this, there are other features such as two antennae, a processor upgrade (A5), a different battery (3.7V, 5.3Whr Li-ion Polymer) and connector, etc. Now, before we get to the dismantling drill, you must know that while most of the internal hardware layout of the iPhone 4S is the same as that of the iPhone 4, the parts are not interchangeable. Let's proceed towards the steps for opening an iPhone 4S now.

• Things you'll need -
  a 5-star screwdriver, a Phillips screwdriver, a jeweler's or watchmaker's screwdriver and an ABS hard prying tool.
• Unscrew and remove the pentalobe, tamper-resistant screws at the bottom using the 5-star screwdriver.
• Now, hold the phone vertically with both hands and push the back panel upwards, using your thumbs. This will easily disengage the back panel.
• Using the Phillips screwdriver, remove the two screws that secure the battery connector. Loosen the battery connector cable gently using the pry tool.
• You'll see a small plastic piece peeping out from the side of the battery. Gently tug on it to take the battery out of its compartment.
• On the top, left-hand side, just above the battery, you'll see a silver metal plate secured by 5 screws. Three of these screws are right there on the plate while two are more towards the right-hand side. Remove all five using your Phillips screwdriver.
• Make sure that you remember which screw belongs where on the metal plate as each of them is of a different size and not paying attention to their placement may result in difficulties while re-assembling the phone.
• Of all the five screws that you remove in the previous step, there is one that secures a black piece of metal, on the right-hand side of the silver metal plate. Detach the black metal piece using your pry tool. You'll discover a screw once you remove it.
• On the left side of the battery compartment, you'll find a small rectangular metal plate, secured horizontally by two screw. Unscrew them and remove the plate to release the dock connector.
• Gently tug at the flex cable, that is revealed on removing the metallic part in the previous step, with your pry tool to loosen and disconnect it.
• Now, slowly and gently, try peeling the flex cable off. It is fixed with an adhesive and you may have to apply some heat to loosen the glue. Be very careful while doing so.
• Use the method mentioned in the previous step to remove the seven flex cables that you've exposed on removing the large silver plat and the black metal piece adjacent to it.
• Pry out the service and network reception appendage and cable using your pry tool. You'll find this right next to the battery compartment and this piece of equipment is a small silver metal piece attached to a black cable that runs parallel to the battery compartment.
• Gently detach the speaker dock by removing the screws that secure it.
• Remove the remaining screws in front of you, including the one behind the warranty sticker. You must be careful not to damage this sticker.
• Once all these screws are undone, you can pop the SIM compartment out by poking the depressed area with your 5-star screwdriver.
• Gently remove the motherboard now, getting a close look at the A5 processor chip we were talking about earlier. It is best to leave the processor unit and its covering alone.
• Now, gently pry out the vibrator. You will now see 6 more screws and 6 washers along the perimeter of the phone. Remove them.
• Last, pry the screen out gently using the pry tool. Be very careful while doing so and do not keep exerting pressure on just one side or at just one point. Pry along all sides, applying slight pressure to each location so that you do not damage the display interface.

There, your iPhone 4S is dismantled and at your disposition for minute scrutiny. Here's how to open you 4 model safely, from scratch but without a scratch!

• Tools you'll need -
  a small screwdriver, a flat-head razor, safe open tool, repair toolkit, paper clip.
• Place your iPhone upon the soft surface and insert the paper clip in the tiny hole that is on top of your smartphone.
• Keep pushing the paper clip in until the SIM card tray appears to be popping out. Take out the SIM tray and keep it separate.
• Unscrew and remove the screws that fix dock in place at the bottom of your iPhone.
• Insert a slim tool from your safe open tool box in between the chrome ring and glass panel in the front, exactly on top of any one of the holes in which a screw was there. Exert slight pressure to disintegrate the display from the back portion.
• Open up the panel, lifting it up from the dock side, without damaging any ribbon or connection.
• Unplug the two ribbons on the secured end and you will find a third ribbon under one of the previous ribbons. Unplug that as well in order to separate the complete display assembly from the iPhone.
• Once you've disengaged the front and display side, you'll see seven screws along the sides. Unscrew them, including the one under the Do Not Remove sticker.
• Unplug the ribbon and, very carefully, take out the motherboard, being meticulously light-handed with the cameras. The iPhone 4 has two cameras - one 1.3 mega pixel camera in front and another 5 mega pixel thingy on the back. Both these cameras are located on their individual motherboards, making it very easy to remove each separately.
• Once the rear camera is removed, you'll see nine screws near the camera compartment. Unscrew them.
• The battery is easy to remove as it is not soldered in place.
• Take out the headphone paraphernalia including the flex cable that is attached to it.
• Take out the vibrator and speaker assembly consisting of the dock connector, antennae and main menu button.
• Turn the iPhone to the front and remove the four screws, two on each side, from the sides.
• Separate the LCD from the glass panel. The LCD panel of the iPhone 4 is very tightly secured and you need to be extra careful not to damage the glass panel and digitizer when exerting pressure to pry out the display.

Opening an iPhone 4 is pretty similar to opening an iPhone 3G. You need to unscrew all the screws and unplug all connections and ribbons. However, there are a few differences here and there that have been discussed as follows:-

• The biggest difference here is that the iPhone 4 has two cameras - one 1.3 mega pixel camera in front and another 5 mega pixel thingy on the back - while iPhone 3 has just one rear camera.
• Another noticeable difference is that when you remove the two screws at the bottom of the iPhone 3, it releases the front, contrary to in case of iPhone 4 where removing these screws releases the back case.

The rest of the drill goes as follows:-

• Tools you'll require -
  safe open tool, paper clip, a small screwdriver, a flat-head razor, repair toolkit.
• Use the paper clip to disengage the SIM as discussed for iPhone 4 above.
• Take the bottom screws that hold the dock in place out.
• Slip a slim tool in between the chrome ring and glass panel in the front, exactly on top of any one of the holes in which a screw was there. Use slight pressure to separate the display from the back panel.
• Lift the panel up from the dock side carefully, avoiding damage to any ribbon or connection.
• Unplug the two ribbons on the secured end. Unplug the third ribbon as well, which can be discovered under one of the two previous ribbons, so that the complete display assembly is separated from the phone.
• Once you've taken out the front and the display side, you'll would discover seven screws. Unscrew and take them out, including the one under the Do Not Remove sticker.
• Unplug the ribbon and very carefully disengage the motherboard, being extra cautious with the camera which is fixed beneath it.
• Gently, pull the battery out, holding on to the attached tab. Carefully extract the camera after taking out the lone screw that is placed nearest to the battery compartment.
• Once the camera is removed, you'll discover nine screws close to the camera compartment. Unscrew them.
• Detach the headphone paraphernalia including the flex cable that is attached to it.
• Remove the vibrator and speaker assembly that includes the dock connector, antennae and main menu button.
• Turn the phone to the front and remove the four screws, two on each side, from the sides.
• Separate the LCD from the glass panel.

Opening iPhone 2 is a somewhat different task than opening all other iPhone models as there are many interlinking parts in it, besides the metal back, that were not included in the subsequent models. You must have patience and proper equipment to get the job at hand done.

• Tools required would include
  a small utility knife, soft surface, paper clip, toothpick and jeweler's screwdriver.
• Place your iPhone upon the soft surface and insert the paper clip in the tiny hole that is on top of your smartphone.
• Keep pushing the paper clip in until the SIM card tray appears to be popping out. Take out the SIM tray and keep it separate.
• Now, turn the iPhone on the smooth surface so that it lies face down and you can see the two tabs at the black connector's edge. Push them in further with the utility knife and take the black connector off your iPhone's case.
• Pry up the antenna cover by pushing in the utility knife between the dock connector and antenna cover.
• Inserting the knife between the antenna cover and the bezel in front, slide it towards one side and move it along the corner till it comes in contact with the metal back. Repeat the process on the other side and take the knife out.
• Separate the rear bottom panel of the iPhone by removing the three screws there, using the jeweler's screwdriver.
• Insert the pointy end of a toothpick inside the small square depression and wiggle it to separate the inner rear panel.
• Pull the panel up and push in the knife between the panel and metal bottom and exert upward pressure to open one corner of the metallic bottom. Repeat on the other side and pry up the bottom off the front of your iPhone 2G using the knife.
• You will see an orange tape around the white antenna cable - peel it off and separate the antenna cables from the logic board using your knife. Unscrew the three screws that you see, using the jeweler's screwdriver, to reveal the camera module.
• Remove the camera by pulling out the camera connection very carefully from the logic board.
• Push the knife in between the front and battery and pry out the battery. Wiggle out the logic board with the knife by pushing it in between the front and the logic board, right where the camera module was previously located.
• Undo all the screws which are securing the front bezel to the iPhone and remove the bezel.

That is all you need to know about how to open iPhone. As far as reassembling is concerned, you need to pay attention to the sequence of the dismantling steps. This is important as you can only reassemble a dismantled gadget by going backwards and reversing the dismantling steps! If necessary, keep written step-by-step instructions in front of you to avoid goofing up. Here's wishing you good luck dismantling and reassembling your iPhone.