diff --git a/nixos/modules/installer/tools/nixos-install.sh b/nixos/modules/installer/tools/nixos-install.sh
index 8685cb345e1..be3b5c0687a 100644
--- a/nixos/modules/installer/tools/nixos-install.sh
+++ b/nixos/modules/installer/tools/nixos-install.sh
@@ -132,8 +132,9 @@ if [[ -z $noBootLoader ]]; then
     echo "installing the boot loader..."
     # Grub needs an mtab.
     ln -sfn /proc/mounts $mountPoint/etc/mtab
-    NIXOS_INSTALL_BOOTLOADER=1 nixos-enter --root "$mountPoint" -- /run/current-system/bin/switch-to-configuration boot
+    export NIXOS_INSTALL_BOOTLOADER=1
 fi
+nixos-enter --root "$mountPoint" -- /run/current-system/bin/switch-to-configuration boot
 
 # Ask the user to set a root password, but only if the passwd command
 # exists (i.e. when mutable user accounts are enabled).
diff --git a/nixos/tests/nixos-install-simple b/nixos/tests/nixos-install-simple
deleted file mode 100755
index c6044eeffb1..00000000000
--- a/nixos/tests/nixos-install-simple
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/bin/sh -eux
-
-mkdir -p "$1"
-
-ROOT="$(readlink -f $1)"
-SYSTEM="$(readlink -f ${2:-./result})"
-
-# create root folders
-mkdir -p "$ROOT/etc" "$ROOT/boot"
-
-# install NixOS
-nix-env --store "$ROOT" \
-  --extra-substituters "auto?trusted=1" \
-  -p "$ROOT/nix/var/nix/profiles/system" --set "$SYSTEM"
-
-# activate NixOS
-touch "$ROOT/etc/NIXOS"
-nixos-enter --root "$ROOT" \
-  -- /run/current-system/bin/switch-to-configuration boot
diff --git a/nixos/tests/systemd-machinectl.nix b/nixos/tests/systemd-machinectl.nix
index f28941bca5a..3438722e321 100644
--- a/nixos/tests/systemd-machinectl.nix
+++ b/nixos/tests/systemd-machinectl.nix
@@ -17,6 +17,7 @@ import ./make-test.nix (let
   }).config.system.build.toplevel;
 
   containerName = "container";
+  containerRoot = "/var/lib/machines/${containerName}";
 
 in {
   name = "systemd-machinectl";
@@ -39,7 +40,7 @@ in {
 
     $machine->waitForUnit("default.target");
     $machine->succeed("mkdir -p ${containerRoot}");
-    $machine->succeed("${./nixos-install-simple} /var/lib/machines/${containerName} ${containerSystem}");
+    $machine->succeed("nixos-install --root ${containerRoot} --system ${containerSystem} --no-channel-copy --no-root-passwd --no-bootloader");
 
     $machine->succeed("machinectl start ${containerName}");
     $machine->waitUntilSucceeds("systemctl -M ${containerName} is-active default.target");