diff --git a/build-ppc-s390-dom.patch b/build-ppc-s390-dom.patch
new file mode 100644
index 0000000..238c440
--- /dev/null
+++ b/build-ppc-s390-dom.patch
@@ -0,0 +1,14 @@
+diff -up firefox-55.0/dom/base/nsWrapperCache.h.old firefox-55.0/dom/base/nsWrapperCache.h
+--- firefox-55.0/dom/base/nsWrapperCache.h.old	2017-08-03 12:02:06.720927791 +0200
++++ firefox-55.0/dom/base/nsWrapperCache.h	2017-08-03 12:03:16.576707873 +0200
+@@ -41,7 +41,7 @@ class nsWindowRoot;
+ // This may waste space for some other nsWrapperCache-derived objects that have
+ // a 32-bit field as their first member, but those objects are unlikely to be as
+ // numerous or performance-critical as DOM nodes.
+-#if defined(_M_X64) || defined(__x86_64__) || defined(__aarch64__)
++#if defined(_M_X64) || defined(__x86_64__) || defined(__aarch64__) || defined(__PPC64__) || defined(__pcc64le__) || defined(__S390X__) || defined(__s390x__)
+ static_assert(sizeof(void*) == 8, "These architectures should be 64-bit");
+ #define BOOL_FLAGS_ON_WRAPPER_CACHE
+ #else
+diff -up firefox-55.0/media/libyuv/libyuv/tools_libyuv/autoroller/unittests/testdata/DEPS.chromium.old firefox-55.0/media/libyuv/libyuv/tools_libyuv/autoroller/unittests/testdata/DEPS.chromium
+diff -up firefox-55.0/media/webrtc/trunk/Makefile.old firefox-55.0/media/webrtc/trunk/Makefile
diff --git a/firefox.spec b/firefox.spec
index 9b6ea34..3fd0df5 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -1,3 +1,4 @@
+ExcludeArch: aarch64 armv7hl
 
 # Use ALSA backend?
 %define alsa_backend      0
@@ -127,6 +128,7 @@ Patch29:        build-big-endian.patch
 Patch30:        fedora-build.patch
 Patch31:        build-ppc64-s390x-curl.patch
 Patch32:        build-rust-ppc64le.patch
+Patch33:        build-ppc-s390-dom.patch
 
 # Fedora specific patches
 # Unable to install addons from https pages
@@ -300,6 +302,7 @@ This package contains results of tests executed during build.
 %patch30 -p1 -b .fedora-build
 %patch31 -p1 -b .ppc64-s390x-curl
 %patch32 -p1 -b .rust-ppc64le
+%patch33 -p1 -b .ppc-s390-dom
 
 %patch3  -p1 -b .arm