diff --git a/mozjs52.spec b/mozjs52.spec
index 198e065..a4fc4aa 100644
--- a/mozjs52.spec
+++ b/mozjs52.spec
@@ -22,10 +22,12 @@ Source0:        https://ftp.mozilla.org/pub/firefox/releases/%{version}esr/sourc
 # Patches from Debian mozjs52_52.3.1-4.debian.tar.xz:
 Patch0001:      fix-soname.patch
 Patch0002:      copy-headers.patch
+Patch0003:      tests-increase-timeout.patch
+Patch0004:      tests-snans-be.patch
 
 # Disable JS Helper threads on ppc64le
 # https://bugzilla.redhat.com/show_bug.cgi?id=1523121
-Patch0003:      disable-extra-threads.patch
+Patch0010:      disable-extra-threads.patch
 
 # Patches from https://github.com/ptomato/mozjs / Debian mozjs52_52.3.1-4.debian.tar.xz
 Patch0101:      disable-mozglue.patch
@@ -72,6 +74,9 @@ pushd ../..
 %patch0001 -p1
 %patch0002 -p1
 %patch0003 -p1
+%patch0004 -p1
+
+%patch0010 -p1
 
 %patch0101 -p1
 %patch0104 -p1
diff --git a/tests-increase-timeout.patch b/tests-increase-timeout.patch
new file mode 100644
index 0000000..f51dc16
--- /dev/null
+++ b/tests-increase-timeout.patch
@@ -0,0 +1,16 @@
+Description: Increase the test timeout for slower buildds
+Author: Adrian Bunk <bunk@debian.org>
+Bug-Debian: https://bugs.debian.org/878284
+
+--- mozjs52-52.3.1.orig/js/src/Makefile.in
++++ mozjs52-52.3.1/js/src/Makefile.in
+@@ -104,7 +104,7 @@ check:: check-style check-masm check-js-
+ 
+ check-jstests:
+ 	$(wildcard $(RUN_TEST_PROGRAM)) $(PYTHON) -u $(srcdir)/tests/jstests.py \
+-		--no-progress --format=automation --timeout 300 \
++		--no-progress --format=automation --timeout 600 \
+ 		$(JSTESTS_EXTRA_ARGS) \
+ 		$(DIST)/bin/$(JS_SHELL_NAME)$(BIN_SUFFIX)
+ 
+
diff --git a/tests-snans-be.patch b/tests-snans-be.patch
new file mode 100644
index 0000000..4e65cd9
--- /dev/null
+++ b/tests-snans-be.patch
@@ -0,0 +1,29 @@
+Description: Fix sort_snans.js test on big endian
+Author: Adrian Bunk <bunk@debian.org>
+Bug-Debian: https://bugs.debian.org/878285
+
+--- mozjs52-52.3.1.orig/js/src/tests/ecma_6/TypedArray/sort_snans.js
++++ mozjs52-52.3.1/js/src/tests/ecma_6/TypedArray/sort_snans.js
+@@ -34,8 +34,20 @@ function testFloat32NaNRanges(start, end
+ // and startHi, startLow and endHi, endLow should be 32-bit integers which,
+ // when combined (Hi + Low), form Float64 NaNs.
+ function testFloat64NaNRanges(startHi, startLow, endHi, endLow) {
+-    let skipN = 10e6;
+ 
++    // Swap on big endian platforms
++    if ((new Uint32Array((new Uint8Array([1,2,3,4])).buffer))[0] === 0x01020304) {
++	let tmp = startHi;
++	startHi = startLow;
++	startLow = tmp;
++
++	tmp = endHi;
++	endHi = endLow;
++	endLow = tmp;
++    }
++
++    let skipN = 10e6;
++
+     let sampleSizeHi  = Math.floor((endHi - startHi)/skipN);
+     let sampleSizeLow = Math.floor((endLow - startLow)/skipN);
+ 
+