A couple days ago, we told you that the unlock for iOS 4.2.1 was in the works. Now, MuscleNerd of the iPhone Dev-Team tweeted that it’s fully functional and going to be released on Sunday, or as MuscleNerd likes to call it, Funday!

Here’s what he had to say:

“Finally got ultrasn0w working fully on 4.2.1. Apple inadvertently(!) broke ultrasn0w via aggressive compiler optimization.”

Some of you may say “the unlock came before the proper jailbreak? Oh it’s useless…” or “The iPhone Dev-Team doesn’t appear to know what they’re doing”… Well, I can only say, you don’t know what the iPhone Dev-Team has accomplished for the whole jailbreak community. Thanks to their hard work, they have made our “i” lives super easy!

Stay tuned to iJailbreak as we’ll bring you step-by-step guides on all your jailbreaking needs.