No, that's not the problem. We do/have like this: when you get your new SIM and plug it in, it connects to the network and the old one is dissabled at the same time, takes about 15-60 min. My new SIM works fine in my N9 and N900. I have a carrier locked phone =/ EDIT: But this i wonder: You can unlock the carrier by going into service menu and enter a code you can buy online. But how do i access the service menu with SFOSX? Android is the *#*#7378432#*#*