diff --git a/gnu-system.am b/gnu-system.am
index 03b4134019..840b76437f 100644
--- a/gnu-system.am
+++ b/gnu-system.am
@@ -372,6 +372,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/glibc-bootstrap-system.patch		\
   gnu/packages/patches/glibc-ldd-x86_64.patch			\
   gnu/packages/patches/glibc-mips-dangling-vfork-ref.patch	\
+  gnu/packages/patches/gmp-arm-asm-nothumb.patch		\
   gnu/packages/patches/gnunet-fix-scheduler.patch		\
   gnu/packages/patches/gnunet-fix-tests.patch    		\
   gnu/packages/patches/gobject-introspection-cc.patch		\
diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index e6d03b184f..8fa90fed3f 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -531,7 +531,7 @@ (define-public gcc-final
     (native-inputs `(("texinfo" ,texinfo-boot0)
                      ,@(package-native-inputs gcc-boot0)))
 
-    (inputs `(("gmp-source" ,(package-source gmp))
+    (inputs `(("gmp-source" ,(bootstrap-origin (package-source gmp)))
               ("mpfr-source" ,(package-source mpfr))
               ("mpc-source" ,(package-source mpc))
               ("binutils" ,binutils-final)
diff --git a/gnu/packages/multiprecision.scm b/gnu/packages/multiprecision.scm
index 377d922a09..ddbfc79965 100644
--- a/gnu/packages/multiprecision.scm
+++ b/gnu/packages/multiprecision.scm
@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014 Mark H Weaver <mhw@netris.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -22,6 +23,7 @@ (define-module (gnu packages multiprecision)
   #:use-module (gnu packages m4)
   #:use-module (guix packages)
   #:use-module (guix download)
+  #:use-module (guix utils)
   #:use-module (guix build-system gnu))
 
 (define-public gmp
@@ -35,7 +37,8 @@ (define-public gmp
                             version ".tar.xz"))
             (sha256
              (base32
-              "0r5pp27cy7ch3dg5v0rsny8bib1zfvrza6027g2mp5f6v8pd6mli"))))
+              "0r5pp27cy7ch3dg5v0rsny8bib1zfvrza6027g2mp5f6v8pd6mli"))
+            (patches (list (search-patch "gmp-arm-asm-nothumb.patch")))))
    (build-system gnu-build-system)
    (native-inputs `(("m4" ,m4)))
    (outputs '("out" "debug"))
@@ -43,7 +46,15 @@ (define-public gmp
                 '(;; Build a "fat binary", with routines for several
                   ;; sub-architectures.
                   "--enable-fat"
-                  "--enable-cxx")))
+                  "--enable-cxx"
+
+                  ;; FIXME: gmp-6.0.0a's config.guess fails on
+                  ;; multi-core armhf systems.
+                  ,@(if (%current-target-system)
+                        '()
+                        (let ((triplet
+                               (nix-system->gnu-triplet (%current-system))))
+                          (list (string-append "--build=" triplet)))))))
    (synopsis "Multiple-precision arithmetic library")
    (description
     "GMP is a library for arbitrary precision arithmetic, operating on
diff --git a/gnu/packages/patches/gmp-arm-asm-nothumb.patch b/gnu/packages/patches/gmp-arm-asm-nothumb.patch
new file mode 100644
index 0000000000..666cf58cf6
--- /dev/null
+++ b/gnu/packages/patches/gmp-arm-asm-nothumb.patch
@@ -0,0 +1,21 @@
+
+# HG changeset patch
+# User Torbjorn Granlund <tege@gmplib.org>
+# Date 1396602422 -7200
+# Node ID 676e2d0f0e4dd301a7066079d2c9326c25c34a40
+# Parent  0194a75b56b21a9196626430af86c5bd9110c42d
+Conditionalise ARM asm on !__thumb__.
+
+diff -r 0194a75b56b2 -r 676e2d0f0e4d mpn/generic/div_qr_1n_pi1.c
+--- a/mpn/generic/div_qr_1n_pi1.c	Thu Apr 03 23:58:51 2014 +0200
++++ b/mpn/generic/div_qr_1n_pi1.c	Fri Apr 04 11:07:02 2014 +0200
+@@ -130,7 +130,7 @@
+ 	     "%2" ((UDItype)(a0)), "r" ((UDItype)(b0)) __CLOBBER_CC)
+ #endif
+ 
+-#if defined (__arm__) && W_TYPE_SIZE == 32
++#if defined (__arm__) && !defined (__thumb__) && W_TYPE_SIZE == 32
+ #define add_mssaaaa(m, sh, sl, ah, al, bh, bl)				\
+   __asm__ (  "adds	%2, %5, %6\n\t"					\
+ 	     "adcs	%1, %3, %4\n\t"					\
+