Hopefully, this is advanced enough to qualify for this post even though I'm very much a noob to the world of pi.
I have a pi3 running in my basement without a monitor plugged in. When I plug a monitor in it has an acceptable resolution, but I won't be using it with a monitor. After reboots, it is running at a VERY low resolution (x414 vertical, I think). At this resolution, it isn't even enough to see the full configuration window content.
I'm having trouble figuring out how to get it to boot up to at least x1024. I would prefer x1200.
Is there a command I can run at boot up that will change the screen resolution to x1200?