11.Notice whether there is “current scaling is 100%” it means box has been adjusted to
normal position
if there’s still black border at either side, it refers to imbalance between box’s screen size
and TV screen, check following
Check whether use HDMI cable provided together with box or not (HDMI cable
together with box is version 2.0 that’s the most compatibility)
Test with other TV screen (if any)
If box setting is normal, use cable together with box but if it still faces the problem,
may check if there’s setting menu for screen size e.g. full screen, expand, fit to
screen, 16:9 or 4:3 etc.