Comment 18 for bug 1918427

There is no need to install flash-kernel here.
It will install flash-kernel in "ephemeral image" which didn't have kernel installed.
https://git.launchpad.net/curtin/tree/curtin/deps/__init__.py?h=21.2#n57

So that means, curtin will never install flash-kernel into real system because flash-kernel was already existing via squashfs/cloudimg/or something else.
(curtin will copy files to real system before install kernel and those above we discuss.)

Maybe we can move `install bootloader` after kernel is installed and enable_update_initramfs.
keep `install_missing_packages` as pre
and add `install_missing_pacakges` or `install bootloader_package` as post