[Nvidia Shield TV & Shield TV Pro (2019) Guides, Ne] Starz04:
Hello mate. it is actually possible to downgrade Shield 2019 to OS 8.2.3. I used this guide and it worked flawlessly: https://florisse.nl/shield/

Obviously huge thanks to the guy who created it as it saves people so much research and trial + error. Basically alot of time saved.

Using this tweak guide, I've deleted close to everything from google and Nvidia (bloatware + data collecting) on the 2019 Shield TV: https://florisse.nl/shield-tweaks/

I've removed the Play Store and Google Play Services, ATV Core Services, ATV Remote Service, Backdrop, Basic Daydreams, Chromecast and many other things.

I don't use Netflix, Amazon Prime Video, Plex etc. So everything was removed from the Shield.

This is my ADB batch file to uninstall pretty much everything unneeded:

adb shell pm uninstall -k --user 0 com.google.android.speech.pumpkin & adb shell pm uninstall -k --user 0 com.google.android.tts & adb shell pm uninstall -k --user 0 com.google.android.videos & adb shell pm uninstall -k --user 0 com.google.android.tvrecommendations & adb shell pm uninstall -k --user 0 com.google.android.syncadapters.calendar & adb shell pm uninstall -k --user 0 com.google.android.backuptransport & adb shell pm uninstall -k --user 0 com.google.android.partnersetup & adb shell pm uninstall -k --user 0 com.google.android.inputmethod.korean & adb shell pm uninstall -k --user 0 com.google.android.inputmethod.pinyin & adb shell pm uninstall -k --user 0 com.google.android.apps.inputmethod.zhuyin & adb shell pm uninstall -k --user 0 com.google.android.tv & adb shell pm uninstall -k --user 0 com.google.android.tv.frameworkpackagestubs & adb shell pm uninstall -k --user 0 com.google.android.tv.bugreportsender & adb shell pm uninstall -k --user 0 com.google.android.backdrop & adb shell pm uninstall -k --user 0 com.google.android.leanbacklauncher.recommendations & adb shell pm uninstall -k --user 0 com.google.android.feedback & adb shell pm uninstall -k --user 0 com.google.android.leanbacklauncher & adb shell pm uninstall -k --user 0 com.google.android.apps.mediashell & adb shell pm uninstall -k --user 0 com.plexapp.android & adb shell pm uninstall -k --user 0 com.zattoo.player & adb shell pm uninstall -k --user 0 com.nvidia.tegrazone3 & adb shell pm uninstall -k --user 0 com.plexapp.mediaserver.smb & adb shell pm uninstall -k --user 0 com.google.android.play.games & adb shell pm uninstall -k --user 0 com.netflix.ninja & adb shell pm uninstall -k --user 0 com.amazon.amazonvideo.livingroom & adb shell pm uninstall -k --user 0 com.amazon.amazonvideo.livingroom.nvidia & adb shell pm uninstall -k --user 0 com.google.android.youtube.tvmusic & adb shell pm uninstall -k --user 0 com.android.vending & adb shell pm uninstall -k --user 0 com.google.android.gms

Keep in mind this is an extensive removal of pretty much everything. Payed apps etc. wont work with such cleanup. Most apps however do work- Kodi, Firefox, SmartTube, Speedtest, Fdroid, AdAware, Aurora Store (with private login, if you want to update some apps), Aptoide, Twitch, all sorts of Emulators etc.

The thing is that Google Play Store automaticall updates itself in the background, even if you disable it (it gets reenabled automatically) and I dont need that. If I want to update something, I will go to Aurora Store or Aptoide and update manually, but I dont want some sheety apps to be doing whatever they want in the background without asking.

And I didnt install a 3rd party Android Launcher, I use the default one, there are no more ads though after removing like 80% of trash bloatware and adware. The Android TV Home version is 2.1.3-320113730-f and I'm on ShieldOS 8.2.3. No ads to be seen and since even the Nvidia-OTA service was removed, it will never update the Shield by itself or even show a notification that there are updates available- which is exactly how I want it. Everything I need works fine in 8.2.3 and if I ever need an update, I will do it manually.

Also, while we're at it- it is possible to skip the initial login after factory restore, as seen on the picture attached. Source of it is:

https://www.reddit.com/r/ShieldAndroidTV/comments/o8tpkx

However it is actually not required to downgrade Android TV Home app to version 2.0.10 to remove ads from the home screen. By simply downgrading to ShieldOS 8.2.3 (down from 9.1.1), the ads were removed from the main screen automatically. Then if you do some additional cleanup (like removing ATV Core Services and disabling autoupdate for Apps in Google Play Store), the ads will never show up.