RealVNC Small Resolution Problem on Raspberry Pi

Because nothing is easy on Linux. If it were not for the staggering amount of user supplied support, wrestling with Linux would be as frustrating as ever. Fortunately, the answers are out there, due to the common denominator of the Raspberry Pi.

I set up VNC Server (RealVNC) on the Pi while it was connected to my HDMI monitor, whose resolution is set to 1080p (aka 1920 x 1080). When I logged in with the VNC Client from Windows, it gave me full resolution. Later, when I had shut down and restarted without the monitor attached (running headless), the Windows client gave me some horrid size like 480 x 320 – something minuscule.

Apparently, when you run headless, it defaults to the lowest possible resolution. To fix this:

$ sudo cp /boot/config.txt /boot/config.backup
$ sudo nano /boot/config.txt

and uncomment/edit:

hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=82

Now reboot:

$ sudo shutdown -r

Had it not been for stackexchange and the raspi forum, I would have been lost. Instead, I got the glorious 1080p as I had expected. Actually, I had expected the client to allow me to set this value, but I suppose it makes sense that it has to be configured at the server.

Remember to revert to the backup config.txt file if you want to connect with some other monitor.

You can also set it to a lower resolution of 1024×768 at 60Hz by:

$ sudo cp /boot/config.txt /boot/config.backup
$ sudo nano /boot/config.txt

and uncomment/edit:

hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=16

You can view more screen resolutions at http://elinux.org/RPiconfig

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