iOS 5.1.1 untethered jailbroken custom IPSW files extracted from Sn0wbreeze 2.9.4 for baseband preservation. As stated earlier, there are no custom IPSW files for A5 devices, only supported devices are iPhone 4/3Gs, iPad 1, and iPod 4G/3G.
I have earlier posted a guide on how to use Sn0wbreeze 2.9.4 to make pre-jailbroken 5.1.1 IPSW, but those of you who are having trouble using it could simply download the files from below. As stated, these files are custom (pre-jailbroken) and once you restore to them, you will have Cydia installed on your device.
You don’t need to jailbreak your device using any other tools. This will also preserve your baseband, which is good for those who rely on software based unlock. Before you could restore to that custom IPSW file, you first have to put your device into PWNED DFU mode using iReb-r5 or Redsn0w. Download IPSW file for your device and follow the tutorial below.
Download Links for iOS 5.1.1 Custom IPSW Files
Download Sn0wbreeze iPhone 4 5.1.1 9B208 Custom IPSW (Added on May 27)
How to Restore to Custom 5.1.1 IPSW Files Using iReb-r5 and iTunes
Step 1: Download 5.1.1 Custom IPSW for your device from above given links.
Step 2: Download iReb-r5 from here and run it. Connect your device to PC
Step 3: Select your device and follow the on-screen instructions to put your device into PWNED DFU mode.
Step 4: Once you are in DFU mode, open iTunes.
Step 5: Press and hold shift, click on Restore, and select the Sn0wbreeze 5.1.1 IPSW file that you just downloaded.
That’s it! Once the restore finishes, you will have Cydia on your screen which means your device is successfully jailbroken.