I was trouble shooting an Error 29 causing my apple 3gs to only display the USB to iTunes graphic and having all attempts at restores fail. I attempted the software hacks - iRecovery, etc., but no luck - unfortunately the battery replacement did not work either. I think I will need to clean the transistors from corrosion as it was dropped in water. Wish I woudl have had a thirsty bag when this first happened. :(
Instructions were spot on and the removal and installations was do-able. Be sure to have a lot of good light, I made the repair toward the end of the day, so the light was fading on me when I was buttoning up the iPhone.
Good light, the right tools and a positive attitude, you can definitely do this repair.