Set Displays for AM572x GP EVM With 0 for LCD and 1 for HDMI, the following options are available:

omapdrm.displays=0,1: represents the original order (LCD is the primary display, while HDMI is the secondary display) omapdrm.displays=1,0: represents reverse order (HDMI is the primary display, while LCD is the secondary display) omapdrm.displays=0: only the LCD is enabled omapdrm.displays=1: only the HDMI is enabled omapdrm.displays=-1: disable all displays

To set one of the options above, stop at u-boot, and setenv for optargs. Run saveenv to save the setting if needed. For example, the setenv below will use HDMI as the primary display.

setenv optargs omapdrm.displays=1,0

Tried " setenv optargs omapdrm.displays=1 ". The LCD was disabled. Matrix started with delay but that may just be the initial boot. Noticed the matrix does boot slowly though so be patient as it may take a minute.