How to restore My Iphone 3g back to 3.1.2?

[JohnCollins]

Yesterday I made the horrible mistake of restoring my jailbroken and unlocked phone resulting in and upgrade to Firmware 3.1.3. I jailbroke my phone but cant unlock it. I've tried everything to restore back to 3.1.2 including Shift-click restore thru itunes using 3.1.2 firmware I downloaded but I keep getting an error 1015. I even tried using redsn0w version 0.9.2 using my 3.1.2 firmware but somehow it activated and jailbreaks my Iphone under the 3.1.3 firmware. I tried downgrading my baseband using fuzzyband but dont have the right bootloader. Ive tried everything. Please help me. How do I downgrade to 3.1.2 so I can use one of the many methods of jailbreaking and unlocking my Iphone 3g.

[th3donking]

Apple no longer allows you to freely downgrade your iPhone software. All firmware installations must be verified with Apple's signature servers. But there is a way, and its a little complicated.

Go to http://www.iphonedownloadblog.com/2010/02/07/downgrade-iphone-3-1-3-to-3-1-2/

They will have the step by step to downgrade