I am trying to automate the installation of Ubuntu Server 18.04 Bionic using a custom ISO. No existing solutions I can find seem to work. All I want to accomplish at this point is to automatically select the language. At least then I can verify I'm not going down another dead-end.
For the ISO, I've started with
ubuntu-18.04-live-server-amd64.iso, and I've updated the ISO to have the following files:
d-i debian-installer/locale string en_US d-i debian-installer/language string en
auth bootloader keyboard us lang en_US langsupport en_US mouse part / --onpart=sda1 --grow rootpw --disabled timezone --utc
default live label live menu label ^Install Ubuntu Server kernel /casper/vmlinuz append boot=casper initrd=/casper/initrd.gz auto file=/cdrom/preseed.cfg locale=en_US languagechooser/language-name=English localechooser/supported-locales=en_US.UTF-8 countrychooser/shortlist=US priority=critical ks=cdrom:/ks.cfg ---
path include menu.cfg prompt 0 timeout 1
I've verified the "live" block is being started by renaming it and seeing that the system will not even boot then.
I've tried numerous combinations of different approaches. This is the simplest test case I can come up with that does nothing but attempt to set the language in every documented way I can find.