Screen resolution on rpi

Hello, searching for a way to adjust the screen resolution of a snap on my Samsung 27" display.

The sample electron app on core rpi4 model b has a resolution of 1920 x 1080 (16:9). Yet there seems to be a 75px border around the app gui.

When plugging in my laptop with ubuntu 23 to the same 27" display at 1920 x 1080, the app is displaying right to the edge with no border.

Other than this border issue, I’m looking at adjusting the resolution to 1280 x 720 (16:9).

Checking the yaml file and maybe some other setting, I’m not finding anything about resolution.

Is there some settings file that determines which resolution the snap service uses on startup?


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This is an issue with your monitor not talking properly to the pi firmware, they have a config.txt option so you can prevent the border, read up about disable_overscan… since on the pi (up to pi4 at least) the firmware actually negotiates the screen settings before starting the OS, there isnt much else you can do on the OS side…

On the RPi, made a change to the /run/mnt/ubuntu-seed/config.txt file, by un-commenting #disable_overscan=1 After reboot, the display is right to the edge.

The core config web page shows that for pi-config, other than pi-config.disable-overscan, there is also,


I added the following to the config.txt file,


and after reboot, only overscan is working. No rotation or change in the display resolution. I tried also on Vizio 47" and again only overscan works.

In that these settings were not found in config.txt file to un-comment, does that mean that the settings are now managed someplace else, or some other issue is preventing them from rotating and changing resolution?