I had that happen once while on an insider build. Updated to the latest build and it could not boot/update/reset. Tried to hard reset and still kept getting the Sad Smiley. Since mine was the unlocked open market model I had to send it back as an RMA since the open market FFU fill will not reflash. They sent me a replacement but it was locked to T-Mobile, which was not the first time they did that, but that is another story for another day...