diff --git a/build-aux/build-self.scm b/build-aux/build-self.scm
index 853a2f328f..f100ff4aae 100644
--- a/build-aux/build-self.scm
+++ b/build-aux/build-self.scm
@@ -250,6 +250,7 @@ interface (FFI) of Guile.")
     (match-lambda
       (('guix 'config) #f)
       (('guix 'channels) #f)
+      (('guix 'build 'download) #f)             ;autoloaded by (guix download)
       (('guix _ ...)   #t)
       (('gnu _ ...)    #t)
       (_               #f)))
diff --git a/guix/build/download.scm b/guix/build/download.scm
index 5431d7c682..ce31038b05 100644
--- a/guix/build/download.scm
+++ b/guix/build/download.scm
@@ -650,7 +650,7 @@ and write the output to FILE."
            (('swhid swhid)
             (match (string-split swhid #\:)
               (("swh" "1" "dir" id)
-               (format #t "Downloading from Software Heritage...~%" file)
+               (format #t "Downloading ~a from Software Heritage...~%" file)
                (false-if-exception*
                 (swh-download-directory id output)))
               (_ #f)))
diff --git a/guix/self.scm b/guix/self.scm
index 3154d180ac..7181205610 100644
--- a/guix/self.scm
+++ b/guix/self.scm
@@ -878,7 +878,8 @@ itself."
                    ("guix/store/schema.sql"
                     ,(local-file "../guix/store/schema.sql")))
 
-                 #:extensions (list guile-gcrypt)
+                 #:extensions (list guile-gcrypt
+                                    guile-json)   ;for (guix swh)
                  #:guile-for-build guile-for-build))
 
   (define *extra-modules*