Have an old Acer Extensa 4620 with a bad internal display. I can access BIOS with the external VGA attached but for some reason the external monitor goes away when I boot up from USB and start the install of Elementary OS. How to I get the external monitor to always stay on during intall/setup of this OS or any for that matter? There is no setting in BIOS for display or external display.
The first thing you should try doing is simply unplugging and re-plugging the VGA connector in after the laptop has booted. This may send the signals of a new monitor being plugged in to Linux which may in turn enable the mirroring of the screen to VGA output.
The next thing you can try is pressing the button that would enable such an output. By default in Elementary this is the Super + P combination of keys to cycle display modes.
If none of this works you now have two basic options:
Try to type the commands needed manually into the system to enable output to the monitor without seeing them. You also won't be able to see any of the output which will make these even more difficult.
Type just the command
sudo apt install openssh-serverwhich will install the SSH server, which then you can use another system on your network to remote into with.
.isoto include the additional commands needed to work out of the box. See this answer on AskUbuntu about how to do that.
The specific command you're likely looking to run is:
xrandr --output VGA-0 --mode 1920x1080_60.00
However, it may be called something else and you can really only easily get the correct listing by running
Also note that if you try to do this over SSH you'll need to run the commands with the
DISPLAY environment variable set, eg:
DISPLAY=:0 xrandr -q
Since by default the SSH session will have no X11 display.
So after some more digging I found a post from 2014 here: https://ubuntuforums.org/showthread.php?t=2209845 Turns out if you add this line: video=LVDS-1:d at the end of the line that shows up when you press the tab button when you are in the unetbootin bootup screen it will send the install to the external monitor.
Thanks to you reply it got me thinking and googled the right question to find that post.