I replaced my damaged iphone 4's digitizer and lcd. While I don't think I was able to get all the screws right, all the parts are securely in place, including the vibrator. I have not put the rear panel on. However, when I hold down the home + sleep button, the case lights up, and the screen lights up, but I get no apple logo. I turned the volume button on and plugged the iphone onto a charger connected to my Mac, and I heard the audio chirp, but no indication of any kind of iOS activity other than a lighter screen.