diff --git a/installer.nix b/installer.nix
index b87a050..6f2631b 100644
--- a/installer.nix
+++ b/installer.nix
@@ -72,7 +72,7 @@ fi
     mount /dev/disk/by-label/nixos /mnt
     mkdir -p /mnt/install-tmp
     export TMPDIR=/mnt/install-tmp
-    nixos-install --flake "${FLAKE_BASE_URL}#${choice}" --no-root-password --no-write-lock-file
+    nixos-install --flake "''${FLAKE_BASE_URL}#''${choice}" --no-root-password --no-write-lock-file
     rm -rf /mnt/install-tmp
     sleep 10
     reboot