It could be that you didn't have a GPS fix when you restarted (did you turn it on in flight or when back on the ground?). You might try depressing the recessed reset button in the pinhole sized hole on the left side of the device to see that changes anything, but I suspect the D1 may have sustained some damage in the fall. Give our support team a ring at 425-402-0433 for further help with this issue.