My Roku stick is doing this too, keeps resetting/restarting REGARDLESS if it's plugged in via USB or in an actual electric outlet. It had been working just fine, then about a month ago it all of a sudden out of the blue kept doing this. There needs to be a fix!!
Having the same problem! Roku stick, few years old now. Worked with no issues for few months, now keeps resetting. Sometimes not even to the home screen before constantly resetting! So annoying! Can't wait to get a new smart TV and not have to rely on this gadget any more! 😕