Answer to: Bootloop after baterry changeI just had the same problem with an iPhone 4s. After I replaced the battery and reassembled the phone it was stuck in a boot loop. First I checked the new battery with a multi meter to make sure it wasn't a bad battery. It checked out okay. I knew the phone worked just fine before changing the battery. Second I took the back of the phone off and plugged in the power cord and the phone turned on just fine. I looked on the inside of the back plate of the phone and where the contact for the battery hits the back of the phone the metal was rubbed off slightly. I replaced the back of the phone with a new back and viola! No more boot loop. Hope this helps!
Answer to: Bootloop after baterry changeI just changed the battery in a 4S and after it was put back together it was stuck in bootloop. I found the problem to be where the pressure contact was meeting the back of the phone. The metal was slightly scraped off on the inside back plate of the phone. It was a matter of deduction. First I thought the new battery was bad, so I checked it with a multi meter. It checked out fine. I knew the phone worked with the old battery. So, I tested the phone with the back off; I removed the back of the phone and plugged the phone in to the charging cord and the problem was gone. I put a new back on the phone and voila! No more bootloop. Hope this helps!