Hactivating Iphone 4

[dark3lf1337]

Hello all,
I have an iphone 4 that i want to hactivate (i am stuck at the emergency call screen), however i cannot figure out the firmware version since i cannot get past the emergency call screen to check. What can I do you jailbreak/hactivate this phone and get past the emergency screen? Help very much appreciated!

[i.Annie]

Use f0recast to see what firmware you are on, then use redsn0w and the according firmware version to jb and hacktivate.

I believe the new redsn0w from the dev team's blog can do iOS 4.2.1 and up. Maybe 4.1? I'm not sure but definitely 4.2.1 and up.