GeoHot has already released a tool, blackra1n to jailbreak iPhone 3.1.2 firmware, which has few bugs in it. The iPhone Dev team is now come up with new jailbreaking and unlocking tool i.e. PwnageTool 3.1.4 for Mac OS X.
PwnageTool 3.1.4 solves all the issues caused by blackra1n. If you have any issues with Apple’s latest firmware, you can create custom IPSW firmware with the help of PwnageTool 3.1.4 and restore it through iTunes. It allows your baseband to remain unlocked at 3.1.2.