Hi, I know most of you already know that you can use the Button Mapper app to change the behaviour of the pointless Netflix and YouTube buttons on the new chromecast remote. But that is a (relatively) expensive solution at a cost of £3.49.
Today I found a free, Open Source app that does the job just as well (if not better!)
The app is in the Play Store, but not in the Android TV store, so you'll need to side load it using your preferred method (I install on my phone, then use x-plore file manager to copy to the chromecast).
https://play.google.com/store/apps/details?id=io.github.sds100.keymapper
It is a little fiddly to setup using the remote control, but is possible and does work.
I'm using my Netflix button as Play/Pause, which is annoyingly missing from the remote!
I use button mapper on my shield remote and remapped the button to YouTube TV. I didn't pay anything for it.