Go to Device Preferences > About > System Update .
Method 2: Manual USB Firmware Update (For "part06.rar" Files) Download ONIDA 55UIB Software part06 rar
Before hunting for external files, always try the built-in system update. This is the safest way to get the latest Android TV OS (like moving from version 10 to 12.1.1). Go to Device Preferences > About > System Update