diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm
index 72c8bd59f340422b3e71dbf2d4b5bbe91d2dedf5..04431ba59675bc64352d69f222e4b583b901430f 100644
--- a/gnu/build/file-systems.scm
+++ b/gnu/build/file-systems.scm
@@ -50,6 +50,13 @@ (define-module (gnu build file-systems)
 ;;;
 ;;; Code:
 
+;; 'mount' is already defined in the statically linked Guile used for initial
+;; RAM disks, but in all other cases the (guix build syscalls) module contains
+;; the mount binding.
+(unless (defined? 'mount)
+  (module-use! (current-module)
+               (resolve-interface '(guix build syscalls))))
+
 ;; Linux mount flags, from libc's <sys/mount.h>.
 (define MS_RDONLY 1)
 (define MS_NOSUID 2)
diff --git a/gnu/system.scm b/gnu/system.scm
index d63804a06c50b85aff6c20324fbe5a3b4fcaced3..efad14596a5043152fee7759f86115ada56343e2 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -689,6 +689,7 @@ (define %modules
       (gnu build linux-modules)
       (gnu build file-systems)
       (guix build utils)
+      (guix build syscalls)
       (guix elf)))
 
   (define (service-activations services)