My iPhone back cracked badly so I decided to buy a new back online. I had the tools to replace it so I thought it would be no big deal. When I went to take the bottom screws out, one was stripped. I looked everywhere and tried everything that I could do aside from buying anything or taking it anywhere. I got so fed up that I took a knife and just pryed the entire back off. I then had to essentially break the screw from the inside. I wouldn't recommend this way because there was glass everywhere and I almost punctured the battery, but it worked for me and now I have a stylish new aluminum backed iPhone 4.