I jailbroke my iPhone 4 iOS 7.0.4 (11B554a) with evasi0n 7. And that's the worse I did with my phone. I am new to iPhone and was just curious about jailbreaking. But that jailbreak corrupted many of my apps including iOS own apps.
I am very very happy with iPhone in its default iOS. I want to restore back to 7.0.4.
P.S: I tried "Erase all data and settings restore" from iPhone settings but the process stucks at spinning wheel after restart.
#Update::
Ok. I did that. I downloaded ipsw of iOS 7.0.4 and tried to install it through shift+restore method through iTunes. But it keeps giving me error 21 again and again. And don't know about it.