No.
No and if were to happen it won't need a firmware update, that's a Google Home screen app thing. It seems they have ageed to let Nvidia opt out.
the latest I installed added 2 rows of "discovery content" advertising garbage I don't even use my shield for.
there's a service you can disable which takes the rows away until you restart and it re-enables the service and back to rows of "buy this service to watch this show" ads
https://9to5google.com/wp-content/uploads/sites/4/2015/06/android-tv.jpg?resize=768,585
If you are like me and only use the shield for emulation and plex/kodi style apps, ignore the update. If you have a bunch of youtube/netflix/prime etc and have been normalized to the intrusions of ads, you'll be right at home
I've ignored the update because it seems like the only real update is bundling the realtor tv network streams.
Ads are available on US and system wide.
No difference on mine. Not seeing any ads on home screen after today's update.