All parts (part01, part02, etc.) must be in the same folder. Extracting part01 will usually combine them into a single file (often named MstarUpgrade.bin or similar).
Use the KIVI Software Support Page where you can enter your TV's serial number (found on the back of the device) to receive the exact, validated firmware for your specific model. Download RT2861V09 3840x2160 16G Kivi 49UP50GU part08 rar
With the TV off, insert the USB. Hold the physical power button on the TV and plug it into power. Release the button when the update screen or LED blinks appear. All parts (part01, part02, etc
Ensure you have the exact match for your model and screen resolution ( With the TV off, insert the USB
Smart TV . This file appears to be one segment (part 8) of a larger firmware package designed for the chassis. Official and Safe Acquisition
Downloading firmware from unofficial sources (like multi-part .rar files from forums) carries risks, including system instability or "bricking" your TV. The safest way to obtain the correct software is through official channels:
Searching for the specific file name suggests you are looking for a multi-part firmware archive for a KIVI 49UP50GU