Force HDMI output on RockPi4


I’m working with a RockPi4 using DietPi. Now I’m facing an issue with a projector which doesn’t get recognized at the startup and the only way I found it to be tricked is starting up with another screen and then switching plugs. I’ve just purchased one of those HDMI plugs that might solve it but, in the meantime and cause I may need it for other purposes what I’ve seen is the “soft” solution which I’ve seen that in other SBCs is as simple as adding “hdmi_force_hotplug=1” in the config.txt. The problem is that at least the distribution of DietPi I am using doesn’t have such file. So, does anybody know where settings like these and also, “splash_disabled=1”, so the boot up prompts don’t appear, can be set up in my environment?

Thanks a lot!

Try dietpi GitHub, ultimately, since rock pi 4 in mainline - there may be kernel option that force hdmi output even if there is no connection

Interesting. I have a Rock 4C+ which, for some reason, just stopped outputting HDMI:

So far nobody’s come up with any ideas on why or how to diagnose it - so would be interested to hear if you find anything…