I just bought a 58" TCL TV with roku built in and could not get it to work with homeassistant. It would go offline after 20 minutes of being powered off. I have my IOT devices in a clan with no internet access but I decided to update the TV and it still didn’t work.

What I found out I had to do was update the TV AND create a roku account so that this would finish the update. I then finally had the fast startup option and enabling that it works now! Even with internet access blocked again.

Hopefully this helps someone else.