So this is a minor update, which fixing only the accuracy of the 3GS battery meter and the stability of some third-party app launches. This update is avaliable via iTunes.
New firmware 3.1.3 also introduces a new version of the baseband, the 05.12.01. So if you need unlock do not update! DevTeam also warns us:
If you care about your jailbreak and unlock, don’t update your device – 3G and 3G(S) owners should pay particular attention to this warning.
PwnageTool and redsn0w are not yet compatible with 3.1.3
Experimenters show that the latest version of redsn0w 0.9.2 is able to jailbreak iPhone 2G, iPhone 3G and iPod touch 1G. Just point it at the 3.1.2 IPSW (download here) after doing update or restore to firmware 3.1.3. Sounds like DevTeam will release an updated version of redsn0w that will handle firmware 3.1.3 officially. They say iPod touch 2G with firmware 3.1.3 is also jailbreakable.
Users report that unlock software, blacksn0w and ultrasn0w, doesn;t work with the new baseband.
Redsn0w is a cross-platform jailbreaking tool for iPhone and iPod Touch. New version redsn0w 0.9.2 supports the latest firmware 3.1.2.
redsn0w 0.9.2 supports:
All iPhones and iPod touches
Windows and Mac OSX (x86)
Apple firmwares 3.0 and 3.1.2
We expect to see Linux version quite soon.
If you need a carrier unlock, redsn0w will handle iPhone 2G by itself (by installing the BootNeuter utility). For the iPhone 3G and iPhone 3GS use Cydia after you’re jailbroken to install ultrasn0w (baseband 04.26) or blacksn0w (baseband 05.11).
If you have a late-model iPhone 3GS, or if you have an iPod touch 2G whose serial number begins with “MC” (newer than week 40 of last year), or any iPod touch 3G, you can use redsn0w to jailbreak but you are currently restricted to “tethered” rebooting. That means you need to connect your device to a computer each time you boot it – so just try no to reboot.
You can download the latest version of redsn0w here.
Sn0wBreeze 2.9.3(pwnagetool for windows, supports tethered jailbreak of iOS 5.1 for iPhone 4, iPhone 3GS, iPod Touch 3G, iPod Touch 4G, iPad; untethered for iPhone 3GS with old bootrom; untethered for iOS 5.0.1, iOS 4, iOS 3 supports Apple TV 2G)
Sn0wBreeze 2.8b11(pwnagetool for windows, supports iOS 5, iOS 5.0.1, tethered jailbreak for iPhone 4, iPhone 3GS, iPod Touch 3G, iPod Touch 4G, iPad, Apple TV 2G; untethered for iPhone 3GS with old bootrom)