iFixit has done it again: precision teardown of the latest gadget, Apple’s iPhone 4. Some good news: the battery is very easy to replace once the two screws on the bottom of the iPhone 4 are removed. The Retina Display (read Retina Display and iPhone 4 for more info) is firmly attached to the chemically-hardened Gorilla glass and the digitizer making it very difficult if not impossible to replace. For complete findings check out iFixit.