The file you are looking for, , is a specific type of firmware update file used for Smart LED TVs , typically those using the TP.HV553.PC821 motherboard.
These files are often large and split into multiple parts (like "part04.rar") to make downloading easier on slower connections. Here is the context behind this specific "SOS" file: What is this file? Download allupgrade v553 sos part04 rar
Extract only the first part; the software (like WinRAR or 7-Zip) will automatically pull data from the others to recreate the single .bin file needed for the TV. How it’s typically used to FAT32. The file you are looking for, , is