The iPhone Dev team have released Pwnage Tool 3.1.5which can create iPhone 3.1.3 custom ipsw files. This latest version of PwnageTool can jailbreak the original iPhone 2G, iPhone 3G, iPhone 3GS(older bootrom only with baseband 04.26.08) and iPod touch (1G and 2G non-MC model) running on iPhone firmware 3.1.3.
The custom .ipsw firmware files created with PwnageTool can update iPhone to firmware 3.1.3 without updating its baseband so that it can be unlocked to run on any carrier SIM. Interestingly iPhone Dev team hasn’t used any new exploit to jailbreak 3.1.3 firmware and is straightforward port of Pwnage2 and 24Kpwn to the new firmware.
Note 1: If you had previously unlocked your device using blacksn0w for iPhone 3GS, then this is NOT for you. iPod touch 3G is also currently not supported.
Note 2: PwnageTool 3.1.5 is for Mac OS X only. Windows users should follow the guide posted here or here in order to jailbreak and unlock iPhone running with firmware 3.1.3.
Download PwnageTool 3.1.5 for Mac OS X
Official Bittorrent Releases
PwnageTool 3.1.5 Torrent – PwnageTool_3.1.5.dmg.5344262.TPB.torrent
SHA1 Sum = 16611fb60d088edd2fa5128e4f95f35d8e56a603
Unofficial Links (Direct Links)
http://www.hackthatphone.net/PwnageTool_3.1.5.dmg
http://www.ipodtouchmasterfr.com/files/PwnageTool_3.1.5.dmg
http://apfelportal.de/host/images/PwnageTool_3.1.5.dmg
http://zombisoft.com/tools/PwnageTool_3.1.5.dmg
http://www.accesoriigsm.net/PwnageTool_3.1.5.dmg
http://files.bestblog.de/iphone/PwnageTool_3.1.5.dmg
Guide to Jailbreak iPhone 3.1.3 with PwnageTool 3.1.5
1. Start PwnageTool 3.1.5 and select your device (iPhone, iPhone 3G,iPod Touch 2G)
2. PwnageTool 3.1.5 will display the firmware installed on your iPhone/iPod Touch
3. Click on NO when following prompt is displayed
“Do you have an iPhone contract that would activate normally through iTunes?“:
4. PwnageTool 3.1.5 will now create the custom .ipsw file for your iPhone which will be jailbroken.
5. Once custom ipws file is created you need to restore iPhone to this custom firmware 3.1.3 created using PwnageTool 3.1.5. Click on Phone icon from iTunes sidebar and now press and hold “Alt” key and click on Restore button in iTunes and then release “Alt” button.
Select custom iPhone 3.1.3 firmware ipsw file when iTunes prompt
6. Now wait for iTunes to complete iPhone 3.1.3 restoration. Once installation is done your iPhone will restart automatically, if you followed all of above steps properly then you will have your jailbroken iPhone with 3.1.3 OS!
Unlock iPhone 3.1.3
Now that you have a jailbroken phone, you can follow our previous guide to unlock iPhone 3.1.3 with UltraSn0w.
Update 1: Download Spirit to Jailbreak iPhone 2G/3G, iPod Touch 2G/3G on OS 3.1.3 and iPad 3.2 (all MC models)
Update 2: Guide to Jailbreak iPhone OS 3.1.3 with Spirit Untethered
Update 3: Guide to Jailbreak iPod Touch 3G OS 3.1.3 with Spirit Untethered
[via]Blogsdna

Hi,
I have iPhone 3GS with old bootrom, It was jailbreaked to OS 3.0.1.
Now I have updated it with OS 3.1.3 using iTunes by mistake.
Is it possible to jailbreak it again?
I have tried all windows based jailbreaking softwares but not succeeded.
Is it possible to jailbreak it on MAC using PwnageTool 3.1.5?
Please reply.
Thanks in advance.
/Harpreet Singh
The best way to jailbreak and unlock your Iphone version 3.1.3 is to use the pwnage tool 3.1.5, download Iphone restore 3.1.2 and let pwnage use this file create the custom 3.1.2 restore and downgrade your Iphone version back to 3.1.2.
Then follow the rest of the steps displayed.
If you dont already have Blackra!n download this and unlock using blackrain its alot easier than using the CYDIA wy explained in the next post Unlock Iphone 3.1.3
Hope this helps you as I have been trying to do this for some time and found this to bethe easiest solution
I have the iPhone 3G with the 3.1.3 firmware on it. I downloaded PwnageTool 3.1.5 and connected my iPhone. When I was asked to select which device I was using… I selected iPhone, then when it attempted to search for a firmware bundle.. it could not find out.. I then switched to Expert Mode and selected my 3.1.3 firmware bundle, but the PwnageTool said that it was the wrong firmware bundle. I honestly think it is impossible to jailbreak the iPhone 3.1.3… Help? I am getting really frustrated…
I have iPhone 3.1.3 3GS
Is it possible to jailbreak it?
Please reply.
Thanks in advance.
If it is a new MC model with newer bootrom, the answer is NO
I have installed 3.1.3 accidentally, now I lost jailbreak, please please help me to jailbreak my phone….
There is hardly anything we can do now. You can only hope for someone here to give an idea
Will I b able 2 upgrade my frn iPhone 4m 3.0.1 to 3.1.2 w/o any prob using 3.1.2ipsw which I had..
I went all of the way through the process of it and i worked great but it wont activate. i am not getting signal and therefore it is not really a phone. What is go wrong?
Hi, I have an Iphone original which was jailbroken using blacksnow on windows and then upgraded to 3.1.3 through itunes as i had a problem of upper area not working ( not responding to touch). everything worked great using pwange tools on mac and now i have a jailbroken iphone with 3.1.3 firmware. But, yes there is this but, the problem of non responsive upper area still remains. anyway, thanks a ton. you guys rock!!!
any firmware any model untethered with spirit
This worked brilliantly. It took me a few turns to get my iPod touch (1g) into DFU mode, but by about the 4th time I got it. Working fine. Pwnage much better than Redsn0w…
Thanks for the post!
(PS. In advanced mode, you should mention that you can choose NOT to have the pineapple logo…. I would have preferred it without
Thanks again