diff --git a/modules/installer/cd-dvd/iso-image.nix b/modules/installer/cd-dvd/iso-image.nix
index 82acac9a3e58..0c0fe9880214 100644
--- a/modules/installer/cd-dvd/iso-image.nix
+++ b/modules/installer/cd-dvd/iso-image.nix
@@ -76,7 +76,7 @@ let
     isoImage.makeEfiBootable = mkOption {
       default = false;
       description = ''
-        Whether the ISO image should be an efi-bootable volume
+        Whether the ISO image should be an efi-bootable volume.
       '';
     };