Help Confirm ATT Galaxy S4 Unlocked??

[Michale32086]

I have a Galaxy S4 that wouldn't read an ATT sim.....

I was hoping that unlocking it would allow me to bypass the issue by using a different carrier..

I put the new sim in and it said INVALID SIM and then prompted me for a network code. I pushed DISMISS per the instructions, but it still wouldn't read the SIM...

Is there any other way of confirming the UNLOCK did work besides the SIM card??

Thanx

 

[backdoc77]

what is your model and firmware?

 

[Michale32086]

Thanx for the reply.

It's an SGH-I337 and the Android Version is 4.2.2

Thanx again.