turbosim will work, but wont let you upgrade the firmware
firmware upgrades are not merely software updates, they sometimes improve general functionality of the phone
even nokia offers firmware upgrades many a times to support faster sms / mailing etc
heres an update for what to do in case your phone gets bricked
also, the iPhone Dev Team is working on a crack for firmware 1.11
read more here >
IPhone: Bricked iPhones Now Working (Calls With iPhoneSIMFree and TurboSIM) - Gizmodo