diff --git a/scripts/installation/arch/aur-builder-setup.sh b/scripts/installation/arch/aur-builder-setup.sh
index c19d6ab..efa7aca 100755
--- a/scripts/installation/arch/aur-builder-setup.sh
+++ b/scripts/installation/arch/aur-builder-setup.sh
@@ -38,7 +38,7 @@ echo "[aur-builder-setup] Configuring sudoers for aur_builder..."
 ${ROOT_CMD} bash -c "echo '%aur_builder ALL=(ALL) NOPASSWD: /usr/bin/pacman' > /etc/sudoers.d/aur_builder"
 ${ROOT_CMD} chmod 0440 /etc/sudoers.d/aur_builder
 
-RUN_AS_AUR=(su - aur_builder -s /bin/bash -c)
+RUN_AS_AUR=(runuser -u aur_builder -- bash -c)
 
 echo "[aur-builder-setup] Ensuring yay is installed for aur_builder..."
 
diff --git a/scripts/installation/arch/package.sh b/scripts/installation/arch/package.sh
index 813cd62..a154520 100755
--- a/scripts/installation/arch/package.sh
+++ b/scripts/installation/arch/package.sh
@@ -47,7 +47,7 @@ echo "[arch/package] Using 'aur_builder' user for makepkg..."
 chown -R aur_builder:aur_builder "${BUILD_ROOT}"
 
 echo "[arch/package] Running makepkg in: ${PKG_BUILD_DIR}"
-su aur_builder -c "cd '${PKG_BUILD_DIR}' && rm -f package-manager-*.pkg.tar.* && makepkg --noconfirm --clean --nodeps"
+runuser -u aur_builder -- bash -c "cd '${PKG_BUILD_DIR}' && rm -f package-manager-*.pkg.tar.* && makepkg --noconfirm --clean --nodeps"
 
 echo "[arch/package] Installing generated Arch package..."
 pkg_path="$(find "${PKG_BUILD_DIR}" -maxdepth 1 -type f -name 'package-manager-*.pkg.tar.*' | head -n1)"
diff --git a/scripts/installation/init.sh b/scripts/installation/init.sh
index f38669b..e7c6dc3 100755
--- a/scripts/installation/init.sh
+++ b/scripts/installation/init.sh
@@ -2,8 +2,8 @@
 set -euo pipefail
 
 if [[ "${EUID:-$(id -u)}" -ne 0 ]]; then
-  echo "[installation/install] Warning: Installation is just possible via root."
-  exit 0
+  echo "[installation/install] ERROR: Installation requires root. Re-run with sudo." >&2
+  exit 1
 fi
 
 echo "[installation] Running as root (EUID=0)."