After the LeTV Super TV upgrade system, many of my friends responded that they could not install a third-party application. In fact, the installation method still existed. The only way you did it was a little mistake. Now let me tell everyone that LeTV is installed correctly. Open the way. First of all: enter the system settings through the settings button on the remote control Step 2: Open General Options The third step is to select the security settings in the universal settings and set the unknown source application to the open state. Then you can freely install the application you want. You can also directly install a third-party TV application market "sofa manager" so that you don't need to use a USB stick every time you install. Sofa butler download address: Sofa butler installer bag" Sofa butler installer bag.apk What application you need to install directly through the sofa butler can directly search the installation.