diff --git a/add-typecasts-in-glTFAssetWriter.inl.patch b/add-typecasts-in-glTFAssetWriter.inl.patch
new file mode 100644
index 0000000..d6d8c89
--- /dev/null
+++ b/add-typecasts-in-glTFAssetWriter.inl.patch
@@ -0,0 +1,40 @@
+From e9ecd6f8a7bce581655d88fe331ed7fc65af310e Mon Sep 17 00:00:00 2001
+From: James Walker <jamesw@frameforge3d.com>
+Date: Wed, 17 Aug 2016 17:35:16 -0700
+Subject: [PATCH] Add typecasts in glTFAssetWriter.inl to fix compile errors
+ about ambiguous constructors, see:
+ <https://github.com/assimp/assimp/issues/980>
+
+This patch is merged e9ecd6f8 and 666d1ce1.
+
+---
+ src/3rdparty/assimp/code/glTFAssetWriter.inl | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/src/3rdparty/assimp/code/glTFAssetWriter.inl b/src/3rdparty/assimp/code/glTFAssetWriter.inl
+index 0fa8556c..f14afc4d 100644
+--- a/src/3rdparty/assimp/code/glTFAssetWriter.inl
++++ b/src/3rdparty/assimp/code/glTFAssetWriter.inl
+@@ -105,7 +105,7 @@ namespace glTF {
+                 type = "arraybuffer";
+         }
+ 
+-        obj.AddMember("byteLength", b.byteLength, w.mAl);
++        obj.AddMember("byteLength", static_cast<uint64_t>(b.byteLength), w.mAl);
+         obj.AddMember("type", StringRef(type), w.mAl);
+         obj.AddMember("uri", Value(dataURI, w.mAl).Move(), w.mAl);
+     }
+@@ -113,8 +113,8 @@ namespace glTF {
+     inline void Write(Value& obj, BufferView& bv, AssetWriter& w)
+     {
+         obj.AddMember("buffer", Value(bv.buffer->id, w.mAl).Move(), w.mAl);
+-        obj.AddMember("byteOffset", bv.byteOffset, w.mAl);
+-        obj.AddMember("byteLength", bv.byteLength, w.mAl);
++        obj.AddMember("byteOffset", static_cast<uint64_t>(bv.byteOffset), w.mAl);
++        obj.AddMember("byteLength", static_cast<uint64_t>(bv.byteLength), w.mAl);
+         obj.AddMember("target", int(bv.target), w.mAl);
+     }
+ 
+-- 
+2.16.1
+
diff --git a/libqt5-qt3d.changes b/libqt5-qt3d.changes
index d4e853a..3b816b2 100644
--- a/libqt5-qt3d.changes
+++ b/libqt5-qt3d.changes
@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Fri Feb 23 07:12:27 UTC 2018 - mlin@suse.com
+
+- Add add-typecasts-in-glTFAssetWriter.inl.patch (bsc#1082475)
+  * Add typecasts in glTFAssetWriter.inl to fix compile errors on s390
+    about ambiguous constructors https://github.com/assimp/assimp/issues/980
+
 -------------------------------------------------------------------
 Thu Feb 22 08:06:32 UTC 2018 - mlin@suse.com
 
diff --git a/libqt5-qt3d.spec b/libqt5-qt3d.spec
index d9eb659..889862c 100644
--- a/libqt5-qt3d.spec
+++ b/libqt5-qt3d.spec
@@ -34,6 +34,7 @@ Url:            https://www.qt.io
 Source:         https://download.qt.io/official_releases/qt/5.10/%{real_version}/submodules/%{tar_version}.tar.xz
 Source1:        baselibs.conf
 Patch0:         use-Assimp-namespace-to-fix-build-for-big-endian.patch
+Patch1:         add-typecasts-in-glTFAssetWriter.inl.patch
 BuildRequires:  fdupes
 BuildRequires:  libQt5Bootstrap-devel-static >= %{version}
 BuildRequires:  libQt5Concurrent-devel >= %{version}
@@ -59,6 +60,7 @@ systems with support for 2D and 3D rendering in both Qt C++ and Qt Quick applica
 %prep
 %setup -q -n %{tar_version}
 %patch0 -p1
+%patch1 -p1
 
 %package -n %libname
 Summary:        Qt 5 3D Addon