had this same problem of constant rebooting, thought i had tried everything and still could not fix it, i changed the case from the wallet one and have never had the problem since, are the others who are having this problem using the HP wallet case ?
had the excessive steps issue after the last update, now goes the opposite way and stops working completely randomly for some reason, have tried restarting the phone also reinstalling microsoft band app, cant find anything wrong in my settings either.
i'm also missing the gadget app have 3 treasure tags that i cant connect although have tried through Bluetooth, was told could use them through bing, but bing seem incompatible with the x3 as well, will look at other options when i find time.