Posted on: 28/11/2019

  # Use the GRUB 2 boot loader.
  boot.loader.grub.enable = true;
  boot.loader.grub.version = 2;
  boot.loader.grub.efiSupport = true;
  boot.loader.grub.efiInstallAsRemovable = true;
  boot.loader.efi.efiSysMountPoint = "/boot";
  # Define on which hard drive you want to install Grub.
  boot.loader.grub.device = "nodev"; # or "nodev" for efi only
  boot.loader.systemd-boot.enable = true;

You then have to mount your EFI boot partition directly on /boot (not /boot/efi)…

Also if you happen to use Virtualbox, don’t forget you also have to enable EFI system support in the settings dialog.