default.target” is not what runs
oem-config. What that target does is link to the default boot stage, either text-mode “
multi-user.target” or GUI mode “
graphical.target”. This file should always be present and point at one of the two above modes.
oem-config is separate software even if one of those stages triggers it.
One way of correcting this (though perhaps not the “proper” way using
systemctl commands), if previously this was text-mode only:
sudo ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target
Similarly, if your default was a GUI, then this should restore it:
sudo ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target
If you want your flash image to start with a user name/pass, then perhaps look at this script:
Do beware though that if you are shipping that product commercially, then a truly “default” name/pass which the whole world knows about might be frowned on in the state of California (Jetson’s used to come with a default name/pass, but laws there are why there was a switch to having the users create the admin name/pass on first boot).