Hi, I'm facing problem with my Samsung Galaxy S Duos. I can't seem to keep it in 3G mode. It displayed 'H' just once and then it has reverted back to 'E' (Edge). I've tried restart many times. It has Andriod 4.0.4 preloaded. I've not rooted it or anything especially as i dont know what it is or how to do that. Any help will be appreciated.