Thanks for your reply.
Yes, I have done factory resets many times on this device, and never a problem. Now when I start the process, I am asked to supply a Roku account, and no matter what I do, update and verify that password, etc., the next step loops back to the screen asking for Roku account info.
This hack has been employed on several smartphones I have purchased over the years, at times when a crooked cop or other swine-like fascist person could have physically accessed the device.
The only other reasonable explanation would be that the hacker is changing the password from numerous different networks I have used, both at home and places like the local library, and is changing the password just after I reset it, in real time, performing the hack specifically when I seek to reconnect the Roku. This would make sense for a ridiculous crooked cop who objects to my watching certain programming on a Roku TV because he is a fascist, ridiculous relic Fundamentalist Christian who can't figure out why nobody wants to attend his insane church. Or pay monthly dues at a club that accepts him. If you surround yourself with a loser who does annoying, anti-Constitutional things like this, you're pretty much a loser.
A boot loop is a known, common hack that involves replacing a line of Firmware or BIOS code with a GoTo command that loops back to another line, indefinitely.
I think Roku needs to devise a method to flash the Firmware or BIOS on their TVs, either remotely or via USB boot process.