diff --git a/bl2/ext/mcuboot/scripts/assemble.py b/bl2/ext/mcuboot/scripts/assemble.py
new file mode 100644
index 0000000..7a38985
--- /dev/null
+++ b/bl2/ext/mcuboot/scripts/assemble.py
@@ -0,0 +1,114 @@
+#! /usr/bin/env python3
+#
+# Copyright 2017 Linaro Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Assemble multiple images into a single image that can be flashed on the device.
+"""
+
+import argparse
+import errno
+import io
+import re
+import os.path
+
+def same_keys(a, b):
+    """Determine if the dicts a and b have the same keys in them"""
+    for ak in a.keys():
+        if ak not in b:
+            return False
+    for bk in b.keys():
+        if bk not in a:
+            return False
+    return True
+
+offset_re = re.compile(r"^#define FLASH_AREA_([0-9A-Z_]+)_OFFSET_0\s+((0x)?[0-9a-fA-F]+)")
+size_re   = re.compile(r"^#define FLASH_AREA_([0-9A-Z_]+)_SIZE_0\s+((0x)?[0-9a-fA-F]+)")
+
+class Assembly():
+    def __init__(self, output, bootdir):
+        self.find_slots(bootdir)
+        try:
+            os.unlink(output)
+        except OSError as e:
+            if e.errno != errno.ENOENT:
+                raise
+        self.output = output
+
+    def find_slots(self, bootdir):
+        offsets = {}
+        sizes = {}
+        with open(os.path.join(bootdir, 'include', 'generated', 'generated_dts_board.h'), 'r') as fd:
+            for line in fd:
+                m = offset_re.match(line)
+                if m is not None:
+                    offsets[m.group(1)] = int(m.group(2), 0)
+                m = size_re.match(line)
+                if m is not None:
+                    sizes[m.group(1)] = int(m.group(2), 0)
+
+        if not same_keys(offsets, sizes):
+            raise Exception("Inconsistent data in generated_dts_board.h")
+
+        # We care about the MCUBOOT, IMAGE_0, and IMAGE_1 partitions.
+        if 'MCUBOOT' not in offsets:
+            raise Exception("Board partition table does not have mcuboot partition")
+
+        if 'IMAGE_0' not in offsets:
+            raise Exception("Board partition table does not have image-0 partition")
+
+        if 'IMAGE_1' not in offsets:
+            raise Exception("Board partition table does not have image-1 partition")
+
+        self.offsets = offsets
+        self.sizes = sizes
+
+    def add_image(self, source, partition):
+        with open(self.output, 'ab') as ofd:
+            pos = ofd.tell()
+            print("partition {}, pos={}, offset={}".format(partition, pos, self.offsets[partition]))
+            if pos > self.offsets[partition]:
+                raise Exception("Partitions not in order, unsupported")
+            if pos < self.offsets[partition]:
+                buf = b'\xFF' * (self.offsets[partition] - pos)
+                ofd.write(buf)
+            with open(source, 'rb') as rfd:
+                ibuf = rfd.read()
+                if len(ibuf) > self.sizes[partition]:
+                    raise Exception("Image {} is too large for partition".format(source))
+            ofd.write(ibuf)
+
+def main():
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument('-b', '--bootdir', required=True,
+            help='Directory of built bootloader')
+    parser.add_argument('-p', '--primary', required=True,
+            help='Signed image file for primary image')
+    parser.add_argument('-s', '--secondary',
+            help='Signed image file for secondary image')
+    parser.add_argument('-o', '--output', required=True,
+            help='Filename to write full image to')
+
+    args = parser.parse_args()
+    output = Assembly(args.output, args.bootdir)
+
+    output.add_image(os.path.join(args.bootdir, "zephyr.bin"), 'MCUBOOT')
+    output.add_image(args.primary, "IMAGE_0")
+    if args.secondary is not None:
+        output.add_image(args.secondary, "IMAGE_1")
+
+if __name__ == '__main__':
+    main()