How do I re-enable my iPhone 4

santiagoanette, follow this advice from Apple. Also, there is a good write up on how to enable it on here. Essentially you have to restore it. " restore on the other hand will return the phone to its default settings and YOU WILL lose all information. You should only do that as a last resort and only do it on the computer that you normally sync with. That way it should restore the last backup. Check on here for directions on how to do that.

The only other thing would be to put your iPhone in DFU and restore, again YOU WILL LOSE all data since the last backup.

DFU Mode

Connect your iPhone to your computer

Turn your iPhone Off

Press and hold the power button for 3 Seconds

While continuing to hold the Power button, press the home button as well for 10 seconds

While holding down the home button, release the power button for another 10 seconds

iTunes should now detect the iPhone in recovery mode, press OK, and restore your iPhone. You may now release the buttons. If you have not reached this point, then you have not entered DFU Mode DFU ModeHope this helps, good luck.