I've spent far too long on this. I've looked through way too many pages to no avail. I've done the jailbreak process at least ten times. I deserve to ask this question in a thread. How do get rid of error 21?! It's driving me crazy! Everything up until the recovery from the custom firmware is going just fine, but it always stops me with error 21. I've been using the tutorial by veryniceipod, and it's just not working. Please, please help.