IPhone 4 models. In fall 2010, pentalobe screws started to replace the Philips screws used in post-repair units in the US and in production units in Japan. The iPhone 4 shipped with iOS 4, which was the newest version of Apple's iOS mobile operating system at the time. iOS 4 introduced a multitasking system, allowing apps to remain "suspended" in memory, perform certain operations in the background, and allowing users to switch between apps using an on-screen menu. It also introduced FaceTime, which allows users to perform video calls between other iPhone, iPad, iPod Touch, and OS X users. The iPhone 4
IPhone Dev Team the "modem firmware" version in the iPhone Settings app.) ultrasn0w 1.2.4 (and later) uses the same AT+XAPP command exploit found in the 05.13.04 baseband to update the iPhone 3GS's baseband to version 6.15.00 (found in the iPad 3G). redsn0w is a program which allows users to jailbreak their iPod touch, iPhone and iPad by using various exploits. The first version released was 0.7 to jailbreak iOS 3.0 on the original iPhone, iPhone 3G and iPod touch 1G/2G. It is updated frequently to jailbreak additional iOS versions. PwnageTool is an iPhone jailbreaking application for Mac OS X that creates custom iOS