My first attempt at burning a CNDV-80MT (East) DVD was successful enough to allow me to complete the firmware update and operate the NAV system. I did eventually find that the POI and Address Search functions worked intermittently - meaning that when it did not work, an attempt to pull up the POI search would just drop me back to the map display. At one point I thought it may be thermal issues, since it seemed to correlate with extreme cold, and after a length of time the system would become more responsive. I did discover over time (> 4 months) that even when it did become responsiv