I had the same problem I formatted mine in FAT16 and then copied su980 the folder to the USB stick at the back USB port because the front does not work. It worked for me every time.
1: Copy the upgrade file(SU980) to the root of USB device.
2: POWER Off the STB and insert the USB device.
3: Place the USB at the back of the Box USB port
4: Press the POWER KEY and CH+ Key at the same time, and power on the STB
5: Please loosen POWER KEY and CH+ Key while the OLED display show "Super up, pls wait...", the STB start update.
6: After update finished ,the OLED would display "finished, please reboot". Please power off the STB and power on to restart the STB.
7: Download finished!
