Well.. I ended up "solving" the problem by installing and Xserver, and making an xinitrc script that pauses for 5 seconds, changes the res with xrandr, then continues.. (For some reason xrandr needs that several-second pause before it's called, or it too throws a "can't find mode" error)

On Tue, 13 Sep 2016 at 12:40 Toby Corkindale <toby@dryft.net> wrote:

Hi,
I have a couple of Intel NUCs (dual core celeron CPUs, Intel chipsets including video (i915 kernel module)) that I'm trying to use for a project.

To simplify matters I was going to use the framebuffer device for video output -- but the HDMI defaults to 1920x1080 and I'd really like to change the resolution to match the projector's native resolution, which is 1024x768.

I've tried using fbset, as in:
$ fbset -geometry 1024 768 1024 768 32
but rather than change the HDMI output, it just makes the console occupy a smaller part of the screen. How useless!

I tried using fbset like this too:
$ fbset 1024x768-32
(where that mode is listed in /etc/fb.modes)
but it just threw some errors back.

Am I doing it wrong? Or is it possible that the framebuffer device for this video device just doesn't let you change the resolution?

I guess it's not a disaster if I install a minimal X setup, but first.. any suggestions for fbset?