Evad3rs Dev-team has just released EvasiOn 1.4 for Windows, Mac OS X and Linux. EvasiOn 1.4 update includes full support of iOS 6.1.2 untethered jailbreak on all iPhones, iPads, and iPods.
Evad3rs team recommended jailbreak users to upgrade their devices to iOS 6.1.2 by restoring then in iTunes instead of using the over-the-air update. You can download iOS 6.1.2 IPSW for iPhone, iPad and iPod Touch from direct links.
You can download EvasiOn 1.4 for Windows, Mac OS X and Linux from source links given below.
EvasiOn 1.4 (Windows)
EvasiOn 1.4 (Mac OS X)
EvasiOn 1.4 (Linux)