I own an iPhone 5s with iOS 8 (or above) locked to T-mobile carrier (USA), although I do not have the original sim. I am stuck on the setup page since I had reset the iPhone to factory setting and it keeps asking me for the original sim which i do not have. (IMEI checks does show that the iPhone is already activated as it was used on the original sim before) However, i put in a new sim from optus carrier (i am now in australia) and the network shows signal with 4G data, I have attached an image of it. Now my question is, is the iPhone sim locked? Can i just unlock the sim or would i have to unlock the iPhone?
afaik if the phone is network locked you'd need to be on the original carrier network to unlock it (then connect on itunes to complete etc) and whatever code is required (if any) must be applied with the original SIM.