Display size supported

Which system do you use? Android, Ubuntu, OOWOW or others?

Android, Ubuntu

Which version of system do you use? Khadas official images, self built images, or others?

Official imagws

Please describe your issue below:

is able to join both DSI ports to get more bigger screen size? and if not, which the biggest screen size supported?

The official firmware does not support the splicing display of two mipi screens. If two mipi screens need to be spliced for display, the DTS configuration needs to be modified.
LCD1 can output up to a maximum 4096x2304@60Hz
LCD2 can output up to a maximum 1920x1080@60Hz