How to tell if iPhone's SIM port is working even though it's locked? Is there any way to know if my phone's SIM port is working, even though it's locked to Sprint and I don't have access to a Sprint SIM? I tried using another one but it says "no sim" instead of "no service". Should I go on with the unlocking or there is something else causing it to say "no sim"?
This is what I did to solve the problem.

Powered the phone down.
I removed the SIM card.
Use a small paper clip and insert in the sim card hole and push firmly. Don't use a large paper clip. While they fit the hole, are too large to push on the mechansim that pops the card up.
I lightly cleaned the SIM card contacts with an alcohol prep swab (the kind they use when you get a shot). Just so you know, I did try dry cleaning the card with a soft cloth at first, but it didn't work for me. Try it, if you don't have the prep swab, it might work for you.
I then made sure the card was dry of the alcohol before I reinserted the card in the phone.

Restarted the phone.

This solved my problem. The phone booted up normally.
I hope it solves your problem too.