Before flashing, confirm your hardware version in the device settings to avoid "bricking" the TV with incompatible software. Standard Flashing Procedure
Contacting Echolink Support directly is the safest way to ensure you receive the correct firmware version for your specific panel resolution (3840x2160). Download RT2861P839 3840x2160 Echolink Smart part06 rar
Place the extracted .bin file (often named allupgrade_... ) onto the root of the USB drive. Before flashing, confirm your hardware version in the
Turn off the TV, insert the USB, and hold the power button (or follow your specific model's key combo) while plugging it back in to initiate the update . insert the USB