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Is official raspberry Pi display workable with rockpi4b ?
Or wave share display with HDMI feature ?
We've only tested HDMI displays with the RockPi 4B. As the official RPi touchscreen is CSI it will most probably not work.
WaveShare has a lot of different displays. Although HDMI displays should generally work, I cannot answer for all WaveShare displays. Do you have a specific one in mind?