I know this is an old post to ask for clarification on, but I wanted to test another phone on my line for a bit, and I wanted to put a GSM sim in my 5X while I'm doing it.. what are the difficulties in swapping to another device, then swapping a different sim into the Nexus while I'm using the other device on my Sprint line? I know I'll probably have to chat to get the swap to work, as I've experienced in the past going from an LTE device to a 3G device and back. It just seems odd that you could swap sims back and forth without issues while it's still active on your Sprint line, but not while it's inactive. Thoughts?