LDD.M538.B138 (a common board used in 4K UHD smart televisions). Resolution: 3840x2160 (4K Ultra HD).
5GB / 4GB configuration (likely referring to flash storage and RAM capacities).
Search for the exact board number () on sites like Kazmi Elecom , Remont-aud , or Firmware.vip , which host "dump" files for LED TV repair. Installation Overview
Copy the extracted file to the root directory of the USB drive (do not put it in a folder).
Do not turn off the power during the update, as this can permanently "brick" the TV's mainboard.