Tethered JB won't let me restore

[GoKyu]

I did a tethered jailbreak last week with my iPhone 4, and now want to try the untethered JB that's out. The problem is, the first step is to restore the phone...when I try to (using iTunes 10.1.1), it gets to the part about "Verifying with Apple", and comes back with:

"This device isn't eligible for the requested build"

How can I restore my phone? I thought these jailbreaks were reversible...

 

[GoKyu]

Never mind...post-Christmas brain fart - had to get it into DFU mode and it's restoring fine