Blank/Black screen on RPi 5 headless

[nguyen-v]

Hello all,

I’ve been having a lot of trouble connecting to a headless Raspberry Pi 5 running Ubuntu 24.04.2 LTS. If I plug in a screen in the Pi, I can connect to it with no issue. If a screen is not connected, I get a blank screen, and after a few minutes:

Here’s what I’ve tried so far:

1) Setting hdmi_force_hotplug=1 in /boot/firmware/config.txt

2) Reinstalling NoMachine both on the client and host. Currently running 8.16.1_1_x64 on windows, and8.16.1_1_arm64 on the Pi.

3) Disabling hardware decoding on Windows with

4) Trying the steps here NoMachine – Connecting To Linux Headless Machines With NoMachine – Knowledge Base

sudo systemctl stop display-manager

sudo /etc/NX/nxserver --restart

5) Disabling Wayland on the Pi in /etc/gdm3/custom.conf

WaylandEnable=false

6) Disabling hardware encoding in Server->Performance->Use hardware encoding on the Pi

I’m out of ideas, so I would be grateful if there is anything I can do to make it work.. Thanks for your help!

[Britgirl]

Hi, you said you followed the instructions in the article about headless https://kb.nomachine.com/AR03P00973 in point 4. Executing the steps there correctly shouldn’t require any further intervention.

If you stop the display server, NoMachine should start its own virtual one. What happens when you stop the display server and restart the nxserver, and then try to connect?

You also wrote ” and after a few minutes:” What happens after a few minutes? Did you mean to attach an image or show an error maybe? Please attach it using the attach tool below.

[nguyen-v]

I’ve solved it since by adding

video=HDMI-A-1:1920x1080M@60D vc4.force_hotplug=1

In /boot/firmware/cmdline.txt

[Britgirl]

Yes, it seems there are a few issues with the latest Ubuntu and RPi5 (not NoMachine issues). You might also consider using XFCE instead of Gnome.

[shaw2pi]

This works for me as well—thanks for sharing!

To future readers:
I am also using an RPi5 with Ubuntu 24, and my local machine is running Ubuntu 22. Both sides have NoMachine version 8.16.1.

When adding video=HDMI-A-1:1920x1080M@60D vc4.force_hotplug=1 to /boot/firmware/cmdline.txt, make sure it remains on the same line as the original content. Do not press Enter; instead, keep everything space-separated on a single line. Otherwise, this will not work.

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