How to unlock iphone 3gs 3.1.2?By Community Writer | Community.Drprem.com / November 9, 2011 I got this iphone 3Gs with OS 3.1.2 in it. It was bought from Japan and I want this to work in my country. When I insert a SIM it asks for a code. Which is the best tool that I can use to unlock iphone 3gs 3.1.2.c Today's Top Articles: