This is often an EMMC dump, meaning it may require a hardware programmer (like the RT809H) rather than a simple USB update.
.rar archive, which must be extracted to obtain the .bin or image file for flashing. Where to Download Download MS638 PC821 3840x2160 REF45 rar
TP.MS638.PC821 Chassis Firmware - скачать бесплатно This is often an EMMC dump, meaning it
: Frequently hosts chassis-specific firmware for universal boards. Important Precautions This is often an EMMC dump