(Also posted this in google home sub)
Making this post to hopefully help out those who have posted (including myself), about not being able to turn on/off your chromecast built in android TVs with a google assistant speaker or hub. Since day one, I’ve been able to turn off my tv with google assistant no problem. But turning it ON never worked. Recently, I also began having trouble with the assistant casting Netflix, it’s says it’s doing it, but nothing happen on the tv (Use to work fine before, YouTube didn’t have this issue). So I yet again went into the tv settings (Hisense U68G in case your wondering), and found an option called “ Cast to Wake”, after enabling this, I was suddenly able to turn my tv on, as well as off, using google assistant on my nest hub. I also have no more problem with the assistant not playing Netflix on tv using voice. So, I’m sure this “wake on cast” may be called something else on your brand of tv, but it’s worth looking for it, seeing if it’s disabled, and turning it on. That’s assuming you’ve done all the other basic trouble shooting like making sure CEC (or whatever it may be called on your brand of tv), is enabled, permissions are set on both the tv and google home, and services are linked in both google home app and the tv settings. Hope this helps someone.
Thank you for this! I have a TCL android tv and have not been able to turn on the TV with my nest hub by voice. I found a setting that was added from a recent firmware update under network and internet setting labelled "network standby." After enabling this all works well.