Since these are generic Chinese boxes, "NWD" might be the board manufacturer. Check sites like 4PDA (Russian forum, use translate) or search specifically for K2001N H3 firmware . The H3 chipset is very common, so even generic H3 firmware usually works on these boxes, though WiFi drivers might differ.
: Use a reliable USB 2.0 or 3.0 flash drive (16GB or smaller works best). Format the drive to FAT32 on your computer. K2001n Nwd Firmware