By Wand Agency
Download link: http://euploadfree.com/EllswerthPeckgray432/jailbreak
You cannot downgrade unless you have a 3.1.2 SHSH file save on Cydia or Sauriks server. If you don't have a SHSH file on Cydia then youre out of luck my friend. All you can do now is wait for a new jailbreak working on 3.1.3. There is 3.1.3 Jailbreak but currently it will only work on a jailbroken 3.1.2 iPhone. Also note that once youve successfully downgraded to 3.1.2, your baseband will not downgrade from 05.12.01 to 05.11.07. Meaning, your iPhone cannot be unlock until a new unlock method is working for 05.12.01. If your iPhone is factory unlocked then good for you, otherwise stick with the iPhone firmware 3.1.2.
This works on the new iPhone 3GS. thanks for linkz76 confirmation.
NOTE: If you get the 3002 Error on iTunes while restoring instead of 1015 or any other error, then you do not have SHSH file on store. You're luck only awaits for a working jailbreak method and unlock for 3.1.3.
FOR WINDOWS USERS:
You can use Command (cmd) on windows instead of Terminal.
To edit hosts file: go to C:\Windows\System32\drivers\etc and open hosts file on a notepad. Save it as is. Don't save it as a txt file.
To do the dscacheutil -flushcache on windows: run cmd, then type "ipconfig /flushdns" (disregard quote)
then hit enter.
then to use irecovery(for windows): run irecovery.exe
everything else is the same as stepbystep.
just to let you know this is not tested yet.
Don't hesitate to ask questions.