Hello everyone, I had an issue with my S4 recently. I wanted to unlock my phone so my I could use it with any carrier so I contacted AT&T and got the unlock code. I also followed their instructions explicitly but the phone wouldn't read the different sim. They gave me an unlock code and told me the phone should ask me for the code as soon as I power it on with a new sim, but when I tried, it only read "Emergency No Sim inserted". The sim I inserted was a T-Mobile sim so I decided to try my friend's AT&T sim, the phone worked perfectly as soon as I inserted the new AT&T sim, there was no need for any unlock code. I need help fast since I need to use the phone internationally and I am leaving in 2 weeks. Thank You.