This 2 year old Roku Ultra (which replaced the Roku 4 I had for the same reason) suddenly, while watching a program, lost its Internet connection and now keeps restarting to a wallpaper with no words.
My Roku 4 died a similar death but I said to myself I'll just upgrade to the Roku Ultra and I did -May 2018.
Here we are again 24 months later with an Ultra that lost internet connection and keeps restarting to a blank wallpaper screen, from which you can do nothing.
My Asus Router App shows the wired connection by there is no data transfer.
Of course everything has been shut off - wait a minute - re start... Router, Modem, TV, Roku, several times to no avail.
ROKU needs to add a disclaimer that owning a Roku Ultra will cost you $50.00 per year.
On my way to get yet another $100.00 Roku Ultra.
So glad my 4K UHD HDR TV, Asus Router and Motorola Modem have a better quality life span.
Cord Cutter since 2014.