You should power off/on the device when switching SIM cards. A hot swap is not supported by Lumia 1520.
- How long does it take to start up my Lumia for the first time?
- What does a flashing start key mean on my Lumia phone?
- Does my Lumia support “Hey Cortana” Voice Activation?
- I forgot my Nokia account password for my Nokia Lumia. How do I recover my account?
- What is error code 80070490 and how do I resolve it?