1 - 2 horas
My lock button would no longer depress unless I applied a large amount of pressure to one side of it. I took my phone apart first, using the guide, to see what exactly was wrong. I was missing the small black button on top of the ribbon cable.
Well, I ended up spending multiple hours doing this repair. A few to open it up the first time, 3.5 to fashion a makeshift button using a piece of a gift card and some superglue, and 2 more to take off the makeshift repair and actually fix it with the new part. Be very careful with the front facing camera retainer. It's very difficult to remove sometimes and the last time I opened up the phone I forgot to blow out the cameras lens and left a piece of dust in it. (if it ever becomes a problem it'll be a super simple fix, but right now it's fine)
If you don't mind spending $25 to fix the button this is an excellent repair. If you can find the part for cheaper, I would suggest looking, but this part was fine. Also, when pulling the old ribbon cable off, be aware of all the rubber pieces on it. All of these rubber parts are necessary. You will need to transfer them over to the new cable if it doesn't come with them already. (mine didn't)
There's a rubber piece on the back of the microphone that keeps the connector from coming into contact with the screws, (I lost it and replaced it with a few sheets of paper) a piece of rubber over the cable on top of the proximity sensor, and one underneath the cable attached to the proximity sensor itself. It has a mirror like finish and a rectangular rubber square around it. Make sure all pieces are transferred over. (if it wasn't necessary, apple wouldnt have included it.)
If you don't want to spend the money, you can cut a very small square out of a piece of plastic (extremely small! About the size of a dot of ink from a pen.) and superglue it to the middle of the underside of the actual button. If when screwing on the bracket the button doesn't work, you'll need to shave the piece of plastic down. Business card width might be better. The button will work, but won't be as easy to press as it was.