I have what's supposed to be an unlocked used iPhone 5 (currently used on Rogers). I wanted to test it out so I put in another carrier's microSIM (Virgin) cut down to nanoSIM size. First it said Searching, then No Service. Under settings > general > about > Carrier it said Bell 16.0 and a pop up prompted me to install a carrier update. Virgin is a Bell subsidiary. I couldn't make any calls, even to 611, to test it out on account of the old SIM. Do I need to get a working SIM to confirm or is this definitive proof that it's unlocked?