" Step By Step Instructions to Downgrade a 3GS From 3.1 to 3.0 9
Accidentally submitted before I was done. These instructions are for Mac. If a mod can edit the title to put (Mac) where it says 9, that would be awesome.

1.) This will only work if you used the "Make My Life Easier" button within Cydia to store your ECIDs.

2.) Download BBEdit from barebones.com

3.) Once installed, open BBEdit, go to "File" then "Open Hidden." Go to Mac HD > Private > etc > hosts and open the hosts file. You will need to go to the dropdown box and select "open all types of files" to select it.

4.) Once you have the hosts file opened, go to the very bottom of the file, and paste "74.208.105.171 gs.apple.com" at the bottom. Go to file > Save.

5.) Put your phone into DFU mode. (With phone plugged in, hold home button and sleep button for ten seconds, then release the sleep button while keeping the home button pushed down, until an iTunes prompt pops up.)

6.) Option + click the Restore button, and point it to iPhone 3.0 OS, and Open.

7.) After the restore process is finished, you can use redsnow 0.8 to jailbreak.

Everything should work. "

I saw this on another forum. Is this possible? Don't want to try it because I only had my iphone 3GS for 2 days LOL

search the forum
if I am not mistaken this "trick" only counts for 3GS phones who were not 3.1 OTB

Ah ok thanks. I got so excited that I forgot to search LOL, I'm so desperate to get my OTB 3.1 unlocked