Both install.img and package_MP.tar can't be modified. Only support upgrade though press power button.

1.copy these two files to the root of the flash drive
2.plug falsh drive to the Movie Cube
3.Press and hold the power button, and do not loosen
4.Plug the power cable into the DC IN jack, wait about 5 seconds or more,
  and then loosen your finger on the power button.
5.no power off during upgrade to prevent a broken board
6.the whole upgrade process will take 30s,system will restart after finishing upgrade
7.if you face any reboot problem or black screen problem after upgrade bootloader,
  pls reinstall the software.
