The LEAP S1 is designed to transmit 4K streaming platform content. But, you must have the corresponding subscription and the connected TV must be compatible with 4K. In addition, the transmission settings must be set to the highest resolution: 4K/2160P.
By default, the LEAP S1 resolution is set to 1080P in order to be supported by most TVs.
If a 4K compatible TV is connected to the LEAP S1, there will be automatic communication via HDMI between the box and the TV to determine the maximum possible resolution.
If this communication via HDMI does not work as it should with some TVs, the issue may be maybe due to the HDMI protocol (CEC) or to an entry-level HDMI cable. In this case, the resolution is set to 1080P by default. To change this setting, you need to go to the « Display » menu and manually select the highest resolution 4K / 2160P.