My Nav VI has the "flickering and Freeze" issues. I thought maybe the issue was tied to the wonder wheel. But just out of the blue it will start changing screens and then not respond to my touch. Then it will start working again. Very frustrating to use as a navigation tool. I am going to try and get a replacement. I will let you all know how it goes. If anyone has any advice on what is causing this, please let me know! And thanks in advance.