Unable to install selected kernel package

[Tong Sun]

My simple Netboot install configuration file doesn't have any kernel specification, except a commented out line of:

#d-i base-installer/kernel/image string linux-generic

It worked all the way up to 18.04, but when I'm trying 19.04 just now, I'm getting:

in-target: Setting up linux-header-5.0.0-13-generic (5.0.0-13.14) ...
in-target: Setting up linux-header-generic (5.0.0-13.14) ...
base-install error: exiting on error base-installer/kernel/failed-install

I'm seeing some related bug reports, e.g.,

https://bugs.launchpad.net/ubuntu/+source/linux-base/+bug/1820755
https://bugs.launchpad.net/ubuntu/xenial/+source/linux/+bug/1820419/

But reading through them, I'm still not too sure what's the cause for mine and what's the fix.

I'm not sure which package to report the error too, and I can't even find any normal linux kernel packages from https://packages.ubuntu.com/search?suite=disco&searchon=names&keywords=linux

which only returns two Package linux-aws & linux-aws-cloud-tools-5.0.0-1004 as of writing.