1.) Browse .ipsw first (add 2.0 firmware)
2.) Click ispw builder
a.) Check Cydia / Youtube activation
b.) Add custom images if you have them
c.) I don't know about payloads
d.) Check what you want
Active phone
Wipe everything
Baseband Updater
Neuter Bootloader
Downgrade 3.9
Unlock
Auto delete
e.) Add bootloaders from Here: Bootloaders
3.) Click build ispw
4.) Whe thats finished click iPwner
5.) Enter DFU mode, Here's how [ame="http://www.youtube.com/watch?v=fiTcKMZfyfk"]Entering DFU Mode[/ame]
6.) Restore new custom firmware in iTunes by holding shift and clicking restore