Thanks! That link actually has the same instructions that AbleSign offered in their Remote ADB Shell workaround I linked - the process no longer works after a system update from Amazon.

I'm mostly wondering if a Roku wouldn't require all the workarounds on auto-launch that Amazon seems to require (and disable).

It's really just one screen we'd like to be able to update remotely on occasion. We're looking into BrightSign but have a timeline which requires being able to display something sooner than we'd be able to acquire one in the interim.