I bought a Roku Ultra ten months ago and for almost a month now while trying the return to the main menu from a video, it crashes. I've got a snow-like screen. Then I have to reboot it. Most of the times it reboots fine, but there have been a couple of times when it doesn't reboot at all, I see the Roku logo but then it goes back to the snowy screen again. Thinking that it could be heating issue, I isolated the unit from the other devices (DVDs, Cable Box, etc) but it is still doing it. Sometimes I have to wait a very long time before trying to reboot it again. Please help.
Have you tried plugging the device into another HDMI port on your TV as well as switching out the HDMI cable used to connect the device?
If the issue is still unresolved, please send me a PM with your Roku account email address, and include the serial number of the Roku device from Settings>System>About. I'll be able to assist you further from there.