diff --git a/modules/installer/cd-dvd/iso-image.nix b/modules/installer/cd-dvd/iso-image.nix
index d775c855ad63..76b4803ccec0 100644
--- a/modules/installer/cd-dvd/iso-image.nix
+++ b/modules/installer/cd-dvd/iso-image.nix
@@ -196,6 +196,8 @@ in
 
   boot.initrd.kernelModules = [ "loop" ];
 
+  boot.kernelModules = pkgs.stdenv.lib.optional config.isoImage.makeEfiBootable "efivars":
+
   # In stage 1, mount a tmpfs on top of / (the ISO image) and
   # /nix/store (the squashfs image) to make this a live CD.
   boot.initrd.postMountCommands =
diff --git a/modules/installer/efi-boot-stub/efi-boot-stub-builder.sh b/modules/installer/efi-boot-stub/efi-boot-stub-builder.sh
index 9df4cb1fe59e..26b2f48fd265 100644
--- a/modules/installer/efi-boot-stub/efi-boot-stub-builder.sh
+++ b/modules/installer/efi-boot-stub/efi-boot-stub-builder.sh
@@ -93,7 +93,7 @@ mkdir -p "@efiSysMountPoint@/efi/nixos/"
 # Remove all old boot manager entries
 if test -n "@runEfibootmgr@"; then
   set +e
-  modprobe efivars
+  modprobe efivars > /dev/null 2>&1
   for bootnum in $(efibootmgr | grep "NixOS" | grep "Generation" | sed 's/Boot//' | sed 's/\*.*//'); do
     efibootmgr -B -b "$bootnum" > /dev/null 2>&1
   done