Hi everyone I have an Iphone 4S with JB 5.1.1 and I've successfully was able to unlock this. My question is that if I want to go back to using my sprint service (put original sim back there) It won't recognize it at all and just says "NO SERVICE". Now before posting I've read on here about setting up some APN settings and using tether me and deleting carrier bundles directory? Before I go further I just want to make sure I'm doing the right thing. How can I use these services back and forth? Let's say I want to use Tmobiles network and then go back to my sprint do I have to remove the gevey tray completely? Or just insert my sprint sim card? I need help. Thank you all in advance.