Extract the first part using WinRAR or 7-Zip ; this will automatically merge all parts into a single folder containing the .bin or image file.
If the TV is stuck on a logo or has a corrupted bootloader, you may need an eMMC programmer like the RT809F or RT809H to write the data directly to the eMMC chip. CFirmware: Lists the NIKAI TP.MS338.PC821 EMMC version. Download MS338 PC821 1920x1080 KODAMA EMMC part3 rar
Installing firmware using the USB port on the service ... - IBM Extract the first part using WinRAR or 7-Zip