diff --git a/guix/build/linux-initrd.scm b/guix/build/linux-initrd.scm
index 5d4446e720..4decc3b15c 100644
--- a/guix/build/linux-initrd.scm
+++ b/guix/build/linux-initrd.scm
@@ -290,7 +290,7 @@ to it are lost."
 
                   ;; Make /root a union of the tmpfs and the actual root.
                   (unless (zero? (system* unionfs "-o"
-                                          "cow,allow_other,use_ino,dev"
+                                          "cow,allow_other,use_ino,suid,dev"
                                           "/rw-root=RW:/real-root=RO"
                                           "/root"))
                     (error "unionfs failed")))