if your iphone is jailbroken and it version 2.2, can you update it to version 3.0 and still be jailbreak?

my iphone is jailbreak and is version 2.2. recently version 3.0 just came out and i want to update my phone to 3.0 (still jailbreak) with out it locking or getting brick. is that possible? if you can answer my question then thank you!