By default, the Quadra firmware is set to HD (1920x1080). But if your TV box and monitor are capable, you can increase (or decrease) the size. Decreasing it is sometimes necessary on some TVs if the sides are slightly cut off, especially older ones.
Select Display from the Applications then Settings menus. A dialog should pop up like this:
Select the resolution you'd like using the Resolution drop-down menu. It will only shown resolutions that your monitor supports.
Some important notes:
1. Don't use Scale. It makes the screen unreadable! For this reason, we don't recommend selecting a 4K resolution as the screen text becomes very tiny. Also, higher resolutions use up more of the shared memory leaving less for your apps. This is especially true on TV boxes with only 2G memory.
2. If the screen is flashing at resolutions greater than HD, try dropping the Refesh rate until the flashing stops.
