If the TV won't turn on, you may need to hold the power button while plugging it in to trigger the update from the USB .

Go to Settings > Device Preferences > About > System Update > Network Update . The TV will automatically detect and install the latest official software .

Is your TV currently , or are you just looking to upgrade the Android version ? How to Update TCL Tv by USB

If you cannot access the menu, contact TCL support to request the official .bin or .zip update file for your region .