diff --git a/firefox.spec b/firefox.spec
index 3bcee4f..89fa3d3 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -131,9 +131,10 @@ Patch305:        mozilla-1245076.patch
 Patch306:        mozilla-1245076-1.patch
 Patch307:        mozilla-1263145.patch
 Patch400:        mozilla-1255590.patch
+Patch401:        mozilla-1266366-branch64.patch
 
 # Debian patches
-Patch401:        mozilla-440908.patch
+Patch500:        mozilla-440908.patch
 
 %if %{?system_nss}
 BuildRequires:  pkgconfig(nspr) >= %{nspr_version}
@@ -279,9 +280,10 @@ cd %{tarballdir}
 %patch305 -p1 -b .1245076
 %patch306 -p1 -b .1245076-1
 %patch400 -p1 -b .1255590
+%patch401 -p1 -b .1266366-branch64
 
 # Debian extension patch
-%patch401 -p1 -b .440908
+%patch500 -p1 -b .440908
 
 %{__rm} -f .mozconfig
 %{__cp} %{SOURCE10} .mozconfig
diff --git a/mozilla-1266366-branch64.patch b/mozilla-1266366-branch64.patch
new file mode 100644
index 0000000..590f745
--- /dev/null
+++ b/mozilla-1266366-branch64.patch
@@ -0,0 +1,29 @@
+# HG changeset patch
+# User Nicolas B. Pierron <nicolas.b.pierron@mozilla.com>
+
+Bug 1266366 - Add branch64 functions to the none-backend MacroAssembler. r=
+
+diff --git a/js/src/jit/none/MacroAssembler-none.h b/js/src/jit/none/MacroAssembler-none.h
+index 512ae81..4441d8d 100644
+--- a/js/src/jit/none/MacroAssembler-none.h
++++ b/js/src/jit/none/MacroAssembler-none.h
+@@ -254,16 +254,18 @@ class MacroAssemblerNone : public Assembler
+     template <typename T, typename S> void branchSub32(Condition, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void branchPtr(Condition, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void branchTestPtr(Condition, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void branchDouble(DoubleCondition, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void branchFloat(DoubleCondition, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void branchPrivatePtr(Condition, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void decBranchPtr(Condition, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void branchTest64(Condition, T, T, S, Label*) { MOZ_CRASH(); }
++    template <typename T, typename S> void branch64(Condition, T, S, Label*) { MOZ_CRASH(); }
++    template <typename T, typename S> void branch64(Condition, T, T, S, Label*) { MOZ_CRASH(); }
+     template <typename T, typename S> void mov(T, S) { MOZ_CRASH(); }
+     template <typename T, typename S> void movq(T, S) { MOZ_CRASH(); }
+     template <typename T, typename S> void movePtr(T, S) { MOZ_CRASH(); }
+     template <typename T, typename S> void move32(T, S) { MOZ_CRASH(); }
+     template <typename T, typename S> void moveFloat32(T, S) { MOZ_CRASH(); }
+     template <typename T, typename S> void moveDouble(T, S) { MOZ_CRASH(); }
+     template <typename T, typename S> void move64(T, S) { MOZ_CRASH(); }
+     template <typename T> CodeOffset movWithPatch(T, Register) { MOZ_CRASH(); }
+