If you obtain the full set of .rar parts, follow these general steps for a USB recovery:
Copy the extracted file to the root directory of the USB drive (do not put it in a folder).
LDD.M538.B138 (a common board used in 4K UHD smart televisions). Resolution: 3840x2160 (4K Ultra HD).
Smart TV, specifically for repair or re-installation purposes. Technical Specifications
Finding this specific firmware often requires visiting specialized TV repair forums or technical databases, as manufacturers like Nordmende do not always host legacy firmware on public-facing sites like the Lumens Download Center .