@Tbu4thanks for sharing this great tip, it worked on my TCL Roku TV. In case the image gets lost (because this is the internet after all), that's Home 5 times, Up, Right, Down, Left, Up (one clockwise circle). I started from the main screen with Home selected in the menu, just in case that's important.
I'm using the Roku purple theme, and the ad box is completely gone. Righteous!
If you're able to get the Secret Menu 2 working (see @Tbu4's reply), some of the items from that screen show the endpoints where images and other things are being served from. That should give you an idea of what to consider blocking (which you'll probably need to do via your incoming router's firewall settings).
Thanks! That worked and appreciated the suggestion.
Thank you @Tbu4 . This solution worked after I restarted the Roku
You’re welcome for posting this. 🙂