diff --git a/gnu/packages.scm b/gnu/packages.scm
index 7f0b58b..57a3e21 100644
--- a/gnu/packages.scm
+++ b/gnu/packages.scm
@@ -30,6 +30,8 @@
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-35)
   #:use-module (srfi srfi-39)
   #:export (search-patch
             search-bootstrap-binary
@@ -70,13 +72,23 @@
         %load-path)))
 
 (define (search-patch file-name)
-  "Search the patch FILE-NAME."
-  (search-path (%patch-path) file-name))
+  "Search the patch FILE-NAME.  Raise an error if not found."
+  (or (search-path (%patch-path) file-name)
+      (raise (condition
+              (&message (message (format #f (_ "~a: patch not found")
+                                         file-name)))))))
 
 (define (search-bootstrap-binary file-name system)
-  "Search the bootstrap binary FILE-NAME for SYSTEM."
-  (search-path (%bootstrap-binaries-path)
-               (string-append system "/" file-name)))
+  "Search the bootstrap binary FILE-NAME for SYSTEM.  Raise an error if not
+found."
+  (or (search-path (%bootstrap-binaries-path)
+                   (string-append system "/" file-name))
+      (raise (condition
+              (&message
+               (message
+                (format #f (_ "could not find bootstrap binary '~a' \
+for system '~a'")
+                        file-name system)))))))
 
 (define %distro-root-directory
   ;; Absolute file name of the module hierarchy.