Use a pair of tweezers to remove the power button from the iPhone.
During reassembly, take note of the correct orientation of the power button. The metal loop should be facing downwards and the outward edges should be on top.
Use the edge of a plastic opening tool to pry the earpiece speaker off the adhesive securing it to the outer case. Note that the power button cable is glued to the the case as well, and will need to be pried up.
Use a pair of tweezers to unfold the earpiece speaker from its recess in the outer case.
Be careful not to tear the cable from the earpiece speaker. They are adhered together, and the cable is very delicate.
The #00 Phillips and 2.5 mm flat head screwdrivers that are suggested tools are too big. I needed to use a #000 Phillips and 5/64 in flat head screwdrivers.
This repair will destroy your soul. I would not recommend even attempting it without even more specialized tools (eye loupe, headlamp, preternatural patience) as it is extraordinarily easy to ruin your phone with one quick misstep. I've thrown in the towel after weeks of attempting the job. After ripping the screen cable for the second and final time, I'm selling for parts.
i did the repair, and my power button is now working, however the loudspeaker is now very pour and i have a lot of noise on then screen when i make a cal, the sensor is working fine, but when i move the phone and look at the screen it is going "crazy" what have i done wrong?