I guess Mr. Tanner still has no response for you ! I found out that the ROKU Ultra has a cooling problem, because their CPU has no cooling system. Maybe you should unplug your ROKU and let it cool down for at least 3 hours. Plug it back again and see what happens, don't forget to take out the MicroSD card if you have one inserted ! If it works, then it's another cooling problem, open the box and apply a cooling pad on the CPU (you can get cooling pads online for about $15). I hope this helps
I have the same issue with a brand new Streaming Stick Plus (3810R). I had the same problem with the first one and exchanged it and the new one does exactly the same thing. Does the update, restarts and just goes to purple screen. Usually restarts itself after a few minutes and goes back to the beginning - wants to update again, etc. Tried a hard reset (holding reset button for 30 seconds) but no change. I see lots of similar posts about the Express. Is it a bad unit (again) or is there an issue with Roku?