That is probably a question to ask google for details…
Basically…
* Enable `allow untrusted Apps` somewhere in the TV settings (Security & Restrictions I think)
* Download an app that can read the USB stick (I use X-plore File Manager)
* Download the correct 8.11 apk from the Android TV release Thread (I use the armv7 for my sony)
* Copythe file to a USB Stick
* Uninstall the current Version on your TV
* Insert USB Stick into TV,
* Use X-plore File Manager to Install Version from USB stick
* Turn off Auto Update Apps in TV
But it appears they have pulled 8.12.2 and are working on a fix ASAP
