My new 740 has frozen twice today during WiFi updating. No response whatsoever on any part of the screen. After unplugging power, I get the "System will be turned...." message. Touching the Cancel button stops the countdown, but the unit is again frozen until power is again removed.
First occurrance about 11:00 am while receiving the Cincinnatti sectional; the second at about 5:00 pm while loading WAC CH-25. Hoping those have some meaning.
In between, I flew about an hour with no problems.