At what stage does an iPhone become carrier locked? Does this happen when the software/iOS is flashed on to the phone? Is there an interaction between the SIM card and the phone upon insertion? Does this vary based on GSM and CDMA networks?
More to the point, I ask because I have an active SIM card with a GSM carrier (which shouldn't need SIM cards, as I recall, but the world has changed since I last knew of these things in detail). Were I to insert this GSM-linked SIM card into a factory unlocked iPhone, what might I expect to happen? Will the new phone fail to join the network because it's an unregistered device? Would the new phone be locked to the new carrier?
For what it's worth, the present iPhone is unlocked (by the carrier).
More to the point, I ask because I have an active SIM card with a GSM carrier (which shouldn't need SIM cards, as I recall, but the world has changed since I last knew of these things in detail). Were I to insert this GSM-linked SIM card into a factory unlocked iPhone, what might I expect to happen? Will the new phone fail to join the network because it's an unregistered device? Would the new phone be locked to the new carrier?
For what it's worth, the present iPhone is unlocked (by the carrier).