diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index a8c821f..0e25c7e 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -250,12 +250,14 @@
   def __init__(self, info_dict, oem_dicts):
     """Initializes a BuildInfo instance with the given dicts.
 
+    Note that it only wraps up the given dicts, without making copies.
+
     Arguments:
       info_dict: The build-time info dict.
       oem_dicts: A list of OEM dicts (which is parsed from --oem_settings). Note
           that it always uses the first dict to calculate the fingerprint or the
           device name. The rest would be used for asserting OEM properties only
-          (e.g.  one package can be installed on one of these devices).
+          (e.g. one package can be installed on one of these devices).
     """
     self.info_dict = info_dict
     self.oem_dicts = oem_dicts
@@ -289,9 +291,15 @@
   def __getitem__(self, key):
     return self.info_dict[key]
 
+  def __setitem__(self, key, value):
+    self.info_dict[key] = value
+
   def get(self, key, default=None):
     return self.info_dict.get(key, default)
 
+  def items(self):
+    return self.info_dict.items()
+
   def GetBuildProp(self, prop):
     """Returns the inquired build property."""
     try:
diff --git a/tools/releasetools/test_ota_from_target_files.py b/tools/releasetools/test_ota_from_target_files.py
index e472363..7c34b7e 100644
--- a/tools/releasetools/test_ota_from_target_files.py
+++ b/tools/releasetools/test_ota_from_target_files.py
@@ -190,6 +190,16 @@
     self.assertRaises(KeyError,
                       lambda: target_info['build.prop']['ro.build.foo'])
 
+  def test___setitem__(self):
+    target_info = BuildInfo(copy.deepcopy(self.TEST_INFO_DICT), None)
+    self.assertEqual('value1', target_info['property1'])
+    target_info['property1'] = 'value2'
+    self.assertEqual('value2', target_info['property1'])
+
+    self.assertEqual('build-foo', target_info['build.prop']['ro.build.foo'])
+    target_info['build.prop']['ro.build.foo'] = 'build-bar'
+    self.assertEqual('build-bar', target_info['build.prop']['ro.build.foo'])
+
   def test_get(self):
     target_info = BuildInfo(self.TEST_INFO_DICT, None)
     self.assertEqual('value1', target_info.get('property1'))
@@ -209,6 +219,12 @@
     self.assertRaises(KeyError,
                       lambda: target_info.get('build.prop')['ro.build.foo'])
 
+  def test_items(self):
+    target_info = BuildInfo(self.TEST_INFO_DICT, None)
+    items = target_info.items()
+    self.assertIn(('property1', 'value1'), items)
+    self.assertIn(('property2', 4096), items)
+
   def test_GetBuildProp(self):
     target_info = BuildInfo(self.TEST_INFO_DICT, None)
     self.assertEqual('build-foo', target_info.GetBuildProp('ro.build.foo'))