Downgrade IOS 6.0.1-6.0 to 5.1.1 (Only A4 and 3GS)

1-Download Redsn0w 0.9.15b3
Windows-https://sites.google.com/a/iphone-dev.com/files/home/redsn0w_win_0.9.15b3.zip?attredirects=0&d=1

Mac-https://sites.google.com/a/iphone-dev.com/files/home/redsn0w_mac_0.9.15b3.zip?attredirects=0&d=1

2-Note:only work if you already jailbroken in 5.1.1) Go to Extras->Even More->Restore

3-Select your ipsw and shsh blobs

4-Let it go (about 5 minutes)

5-Bamm you're at 5.1.1