External Bootloader Backends
NixOS has support for several bootloader backends by default:
systemd-boot, grub, uboot, etc. The built-in bootloader backend
support is generic and supports most use cases. Some users may
prefer to create advanced workflows around managing the bootloader
and bootable entries.
You can replace the built-in bootloader support with your own
tooling using the external bootloader option.
Imagine you have created a new package called FooBoot. FooBoot
provides a program at
${pkgs.fooboot}/bin/fooboot-install which takes
the system closure’s path as its only argument and configures the
system’s bootloader.
You can enable FooBoot like this:
{ pkgs, ... }: {
boot.loader.external = {
enable = true;
installHook = "${pkgs.fooboot}/bin/fooboot-install";
};
}
Developing Custom Bootloader Backends
Bootloaders should use
RFC-0125’s
Bootspec format and synthesis tools to identify the key properties
for bootable system generations.