just to add to this. Received my N770 yesterday and tried to use it with my Tytn running Wm6. Saw this thread and installed the WM6_DUN cab, but it still didn't work. Tried it this morning with a pre wm5/6 smartphone and it still didn't access the net, so something else was up Eventually looked at the settings that the 770 had setup for the tmobile UK connection and saw that instead of *99# it had put some additional characters in. Changed it, and now it works great ! So no need for me to change to OS 2007 HE, it works fine on OS2006