Installing NetBSD with an old CRT monitor

[Imoen <imoen%labriquerouge.fr@localhost>]

Hi,

I’m trying to install NetBSD on a computer of mine, but I only have an old IBM 
CRT monitor. Unfortunately that monitor doesn’t support display resolutions 
above 640x480, which the computer isn’t able to detect properly. When a higher 
resolution is set, the screen is garbled and hardly readable. I say “the 
computer”, because the BIOS menu itself is garbled.

What I’ve been able to do so far is, when I boot on my installation media, I 
can select option 2 in the bootloader, to get a bootloader prompt. In there, I 
can type in “text 7” which sets a 80x24 screen size and coincidentally switch 
the display resolution to 640x480. I can also switch the display resolution 
with “gop 1”, though it doesn’t look as great if I don’t also switch the text 
mode.

After that, my screen is nice and readable, that is until I run “boot”, the 
netbsd kernel takes over from the bootloader, and resets the screen.

I’ve tried to “userconf disable i915drmkms”, because my graphic card being an 
Intel I assumed it was the one reseting the display settings.

I’ve tried to “userconf disable acpivga”, because after booting the kernel I’ve 
been able to take a glance at “dmesg” output and managed to read that my 
display driver is acpivga. It didn’t work, as even after running this command 
the display is still managed by acpivga.

I’ve tried to “boot -2”, because the manual page says it’s supposed to disable 
acpi (and surely acpivga can’t work without acpi, can it?), but to no avail, my 
display being still managed by acpivga.

Since I’ve been unable to have my bootloader display setting persist after 
loading the kernel, I’ve tried to change display setting from netbsd. So I 
tried to “wsconscfg -t 80x24 -e vt100 1”, but it says to me the device is 
not configured. The same command without “-t 80x24” seems to succeed, but there 
are no visible changes. Same results with display 2 or above, but changing to 
them with Ctrl-Alt+Fn does not show a usable prompt, so maybe I’m missing 
something.

So I’m currently stuck. Any help or pointers appreciated.
Thanks,
Imoen