Thanks for your first post in the Roku Community!
We appreciate you for letting us know about the behavior you're seeing with your Roku device, along with all of the troubleshooting that you've done.
For troubleshooting purposes, have you tried connecting those Roku devices to another TV to see if you are experiencing the same issue with the flashing purple light?
In addition, we also suggest restarting your Roku device, you can either unplug the power cable, wait a moment, and then reconnect it. Or you can use the following steps to restart it from the Settings menu:
- Press Home on your Roku remote
- Scroll and select Settings
- Select System
- Select Power. If you do not see a Power submenu, skip to the next step.
- Select System restart
If the issue persists, please refer to the support article here for additional troubleshooting steps: What to do if you cannot see the picture from your Roku® streaming player on your TV | Official Roku...
Please keep us posted and we'll continue assisting you from there.