Yesterday the Dev Team released the latest of PwnageTool which will allow all iDevices with the older bootrom (i.e. not iPod touch 3G, iPod Touch 2G (MC Model), or newer iPhone 3GS owners) to create a custom jailbroken OS 3.1.3 firmware file. This firmware file will contain the older base-band so if you have unlocked with blacksn0w you should NOT use it. This tool is for Macs only – there is no Windows version.
If you are on a Windows machine, however, you can use the current version of Redsn0w. When it asks to browse for the firmware, browse for the
3.1.2 firmware… it works the same.
Please be sure to read the whole post by the Dev Team HERE before you go ahead and jailbreak your iDevice.