Multi-part RAR archives (like "part06.rar") are often found on specialized technical forums when the file size is too large for a single upload.
Copy only the extracted file (often named upgrade_loader.pkg or similar) to the root directory of the USB drive—do not put it in a folder. Download RSAG7 820 7918 Hisense HxxA6100 Series part06 rar
Visit the Hisense Firmware Download page and enter your TV's Serial Number to see available updates. Multi-part RAR archives (like "part06