I had a similar issue in 2021, however, the solutions that I found then no longer work so I am creating another post in hopes someone can help. I have not found another post with a solution so hopefully there is one.
MineOS won’t boot after USB is removed
Basically I can get through all the installation stages and reboot, however, after rebooting the screen remains black. The server is on as the fans are running and the power LED is on but the screen shows no life except to say, “no signal: entering sleep mode” or something along those lines. I have tried everything I can think of but have no solutions yet. I do not get any error messages. The only thing that I notice is that immediately after I reboot and a whole bunch of code flashes across the screen everything says OK except for one.
[FAILED] Failed unmounting run/live/medium
I am a bit pinched for time so I can give a more detailed account later if needed but if anyone has any immediate ideas that would be great.