I have jailbroken my iPhone 4 on iOS6 and installed the Unlock iOS6 Maps tweak to enable turn by turn navigation. It works fine, apart from no maps show up, I just get the grid without any map overlay. Navigation works fine (it knows where I am and shouts instructions), and I have a strong 3G signal so it shouldn't have a problem downloading them. Anyone have this problem, or have any ideas? Thanks!