It’s been eons since I used Xvfb for anything but you’re starting it via rc.local
or other means with your preferred resolution?
Here’s the overview:
https://www.x.org/releases/X11R7.6/doc/man/man1/Xvfb.1.xhtml
Depending on your x server settings, you may need to also allow access to your client with:
xhost + client_IP
You can check your X log to see if there are any denied connections from your client.
Remote vnc connections can typically specify the alternate display with:
sbc_IP:DISP_#
I haven’t tried x11-vnc
, is this the guidance you’re using?
https://wiki.archlinux.org/title/X11vnc
Perhaps worth trying TigerVNC or another daemon?
Depending on what x-app(s) you need to run, you can also forward them over ssh. For instance, connecting with:
ssh -X user@sbc_IP
Will allow you to run xterm
or firefox
and have them launch on your local system. Depending on your client system, you may need to run a X emulator.
Over WAN connections you may also want to add the -C flag to enable compression.
Here’s to your weekend!