If WinRAR reports a "Checksum error," you can try the "Keep broken files" option in WinRAR settings as a last resort.
Copy the extracted firmware file (often named allupgrade_...pkg or similar) directly to the root directory of the USB—do not put it in a folder. The "Power Key" Method: Turn off the TV and unplug it from the wall. Insert the USB drive. Download HV553 3840x2160 part07 rar
The standby light should begin to blink rapidly, indicating the update is in progress. If WinRAR reports a "Checksum error," you can