I own a Samsung Galaxy Grand Duos and it works perfectly fine, but I have one problem with it. Every time I'm on the phone and try to send messages, it won't let me use sim card 1. I am only able to send using sim card 2
But if I don't have an ongoing call, I can send messages using either sim card. The only time I cant send messages using sim card 1 is when I having an ongoing call.