The Chinese text in the "how to" file says it must be a 8 or 16 GB FAT 32 flash drive:
"Extract this file 2. Access all files to a clean drive disk do not place in the folder to avoid reading failure (FAT32- 8/16G) 3. Plug in the USB slot on the left side of the machine 4. Turn on the power 5. Auto update Wait for the series of beeps to end and enter the boot screen 6. Turn off the power and remove the USB stick 7. Power on ----- complete the update"