iPhone 2G, 3G, 3GS users can now safely update to 3.1.2 firmware without updating the baseband (for unlock). If you are not the one to download all the various files and just want the ultimate result, these files are waiting for you to download! If you rather want to start from scratch, download Pwnage 3.1.4 tool for Mac.
Caution #1 : A restore is going to wipe the iPhone clean. Hence, please backup your iPhone using iTunes and then proceed.
More info about these custom firmware files :
Has factory boot logos …