Step 3: Create the custom firmware using the file you just downloaded.
Step 4: When the custom firmware is complete, your program will prompt you into DFU mode. After that, open iTunes and press option+restore (if you use mac) or shift+restore (if you use windows) and select the custom firmware you just created.
Step 5: After the restoration has finished, download greenpois0n from here.
Step 6: Follow the on-screen instructions. After the iphone reboots, you will find an app called “Loader” on your springboard. Open it, and install Cydia.
Step 7: After installing Cydia, follow my guide on how to add installous and you’re done!
Step 8: Add http://repo666.ultrasn0w.com/ and download ultrasn0w to unlock your phone to any carrier.