diff --git a/gnu/image.scm b/gnu/image.scm
index e10a495d3d2..e347089b342 100644
--- a/gnu/image.scm
+++ b/gnu/image.scm
@@ -70,7 +70,7 @@
   (label                partition-label (default #f))
   (uuid                 partition-uuid (default #f))
   (flags                partition-flags (default '()))
-  (initializer          partition-initializer (default #f)))
+  (initializer          partition-initializer (default #f))) ;gexp | #f
 
 
 ;;;
diff --git a/gnu/system/image.scm b/gnu/system/image.scm
index f1739a35c1b..60ae38f6d89 100644
--- a/gnu/system/image.scm
+++ b/gnu/system/image.scm
@@ -374,7 +374,8 @@ used in the image."
              (type (partition-file-system partition))
              (image-builder
               (with-imported-modules*
-               (let ((initializer #$(partition-initializer partition))
+               (let ((initializer (or #$(partition-initializer partition)
+                                      initialize-root-partition))
                      (inputs '#+(list e2fsprogs fakeroot dosfstools mtools))
                      (image-root "tmp-root"))
                  (sql-schema #$schema)
diff --git a/gnu/tests/base.scm b/gnu/tests/base.scm
index 8284446868b..353d6d415ae 100644
--- a/gnu/tests/base.scm
+++ b/gnu/tests/base.scm
@@ -637,7 +637,6 @@ in a loop.  See <http://bugs.gnu.org/26931>.")
                    (size 'guess)
                    (offset (* 512 2048))          ;leave room for GRUB
                    (flags '(boot))
-                   (initializer #~initialize-root-partition)
                    (label "root-under-test")))))) ;max 16 characters!
 
   (define observer-os