diff --git a/firefox.spec b/firefox.spec
index 7a7dda9..c68f883 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -111,6 +111,8 @@ Patch3:         mozilla-build-arm.patch
 Patch18:        xulrunner-24.0-jemalloc-ppc.patch
 # workaround linking issue on s390 (JSContext::updateMallocCounter(size_t) not found)
 Patch19:        xulrunner-24.0-s390-inlines.patch
+# backport js/src/configure.in changes for secondary arches
+Patch20:        xulrunner-32.0-backport-js-src-configure-in.patch
 
 # Fedora specific patches
 # Unable to install addons from https pages
@@ -224,6 +226,7 @@ cd %{tarballdir}
 %endif
 %patch18 -p2 -b .jemalloc-ppc
 %patch19 -p2 -b .s390-inlines
+%patch20 -p2 -b .js-configure
 
 # For branding specific patches.
 
diff --git a/xulrunner-32.0-backport-js-src-configure-in.patch b/xulrunner-32.0-backport-js-src-configure-in.patch
new file mode 100644
index 0000000..1172c7f
--- /dev/null
+++ b/xulrunner-32.0-backport-js-src-configure-in.patch
@@ -0,0 +1,92 @@
+#Based on: 
+#https://hg.mozilla.org/mozilla-central/rev/57852745f33b
+#https://hg.mozilla.org/mozilla-central/rev/926f47807112
+#https://hg.mozilla.org/mozilla-central/rev/a7b832e15a34
+--- firefox-32.0/mozilla-release/js/src/configure.in	2014-08-26 05:37:57.000000000 +0200
++++ configure.in	2014-09-12 09:30:32.252623444 +0200
+@@ -1313,10 +1316,10 @@
+                result="yes", result="no")
+ AC_MSG_RESULT("$result")
+ if test "$result" = "yes"; then
+-    AC_DEFINE(HAVE_64BIT_OS)
+-    HAVE_64BIT_OS=1
++    AC_DEFINE(HAVE_64BIT_BUILD)
++    HAVE_64BIT_BUILD=1
+ fi
+-AC_SUBST(HAVE_64BIT_OS)
++AC_SUBST(HAVE_64BIT_BUILD)
+ AC_LANG_RESTORE
+ fi # COMPILE_ENVIRONMENT
+ 
+@@ -1404,7 +1407,7 @@
+ *-aix*)
+     AC_DEFINE(AIX)
+     if test ! "$GNU_CC"; then
+-        if test ! "$HAVE_64BIT_OS"; then
++        if test ! "$HAVE_64BIT_BUILD"; then
+             # Compiling with Visual Age C++ object model compat is the
+             # default. To compile with object model ibm, add
+             # AIX_OBJMODEL=ibm to .mozconfig.
+@@ -1748,7 +1763,7 @@
+ 
+     case "$target" in
+     i*86-*)
+-        if test "$HAVE_64BIT_OS"; then
++        if test "$HAVE_64BIT_BUILD"; then
+             AC_MSG_ERROR([You are targeting i386 but using the 64-bit compiler.])
+         fi
+ 
+@@ -1983,39 +1998,34 @@
+ i?86-*)
+     ENABLE_ION=1
+     AC_DEFINE(JS_CPU_X86)
+-    AC_DEFINE(JS_NUNBOX32)
+     ;;
+ x86_64*-*)
+     ENABLE_ION=1
+     AC_DEFINE(JS_CPU_X64)
+-    AC_DEFINE(JS_PUNBOX64)
+     ;;
+ arm*-*)
+     ENABLE_ION=1
+     AC_DEFINE(JS_CPU_ARM)
+-    AC_DEFINE(JS_NUNBOX32)
+     ;;
+-sparc*-*)
+-    if test ! "$HAVE_64BIT_OS" ; then
++sparc-*)
+ dnl ENABLE_ION=0
+     AC_DEFINE(JS_CPU_SPARC)
+-    AC_DEFINE(JS_NUNBOX32)
+-    else
+-    AC_DEFINE(JS_CPU_SPARC64)
+-    AC_DEFINE(JS_PUNBOX64)
+-    fi
+-    ;;
+-powerpc64-*)
+-    AC_DEFINE(JS_CPU_PPC64)
+-    AC_DEFINE(JS_PUNBOX64)
+-    ;;
+-powerpc-*)
+-    AC_DEFINE(JS_CPU_PPC)
+-    AC_DEFINE(JS_NUNBOX32)
+     ;;
+ mips*-*)
+     AC_DEFINE(JS_CPU_MIPS)
+-    AC_DEFINE(JS_NUNBOX32)
++    ;;
++esac
++
++case "$target" in
++mips*-*)
++     AC_DEFINE(JS_NUNBOX32)
++     ;;
++*)
++    if test "$HAVE_64BIT_BUILD" ; then
++        AC_DEFINE(JS_PUNBOX64)
++    else
++        AC_DEFINE(JS_NUNBOX32)
++    fi
+     ;;
+ esac
+