diff --git a/buildbot/cbuildbot_commands.py b/buildbot/cbuildbot_commands.py
index 84d3a9e..4958bc8 100644
--- a/buildbot/cbuildbot_commands.py
+++ b/buildbot/cbuildbot_commands.py
@@ -17,6 +17,7 @@
 from chromite.buildbot import cbuildbot_config
 from chromite.lib import cros_build_lib as cros_lib
 from chromite.lib import locking
+from chromite.lib import osutils
 
 _DEFAULT_RETRIES = 3
 _PACKAGE_FILE = '%(buildroot)s/src/scripts/cbuildbot_package.list'
@@ -36,6 +37,7 @@
 _AUTOTEST_RPC_CLIENT = ('/b/build_internal/scripts/slave-internal/autotest_rpc/'
                         'autotest_rpc_client.py')
 _LOCAL_BUILD_FLAGS = ['--nousepkg', '--reuse_pkgs_from_local_boards']
+_UPLOADED_LIST_FILENAME = 'UPLOADED'
 
 class TestException(Exception):
   pass
@@ -780,13 +782,49 @@
   return os.path.basename(debug_tgz)
 
 
-def UploadArchivedFile(archive_path, upload_url, filename, debug):
+def AppendToFile(file_path, string):
+  """Append the string to the given file.
+
+  This method provides atomic appends if the string is smaller than
+  PIPE_BUF (> 512 bytes). It does not guarantee atomicity once the
+  string is greater than that.
+
+  Args:
+     file_path: File to be appended to.
+     string: String to append to the file.
+  """
+  osutils.WriteFile(file_path, string, mode='a')
+
+
+def UpdateUploadedList(last_uploaded, archive_path, upload_url, debug):
+  """Updates the list of files uploaded to Google Storage.
+
+  Args:
+     last_uploaded: Filename of the last uploaded file.
+     archive_path: Path to archive_dir.
+     upload_url: Location where tarball should be uploaded.
+     debug: Whether we are in debug mode.
+  """
+
+  # Append to the uploaded list.
+  filename = _UPLOADED_LIST_FILENAME
+  AppendToFile(os.path.join(archive_path, filename), last_uploaded+'\n')
+
+  # Upload the updated list to Google Storage.
+  UploadArchivedFile(archive_path, upload_url, filename, debug,
+                     update_list=False)
+
+
+def UploadArchivedFile(archive_path, upload_url, filename, debug,
+                       update_list=False):
   """Upload the specified tarball from the archive dir to Google Storage.
 
   Args:
     archive_path: Path to archive dir.
     upload_url: Location where tarball should be uploaded.
     debug: Whether we are in debug mode.
+    filename: Filename of the tarball to upload.
+    update_list: Flag to update the list of uploaded files.
   """
 
   if upload_url and not debug:
@@ -797,6 +835,10 @@
     cros_lib.RunCommandCaptureOutput([_GSUTIL_PATH, 'setacl', _GS_ACL,
                                       full_url])
 
+    # Update the list of uploaded files.
+    if update_list:
+      UpdateUploadedList(filename, archive_path, upload_url, debug)
+
 
 def UploadSymbols(buildroot, board, official):
   """Upload debug symbols for this build."""
@@ -1072,9 +1114,7 @@
     set_version: Version of output directory.
   """
   latest_path = os.path.join(bot_archive_root, 'LATEST')
-  latest_file = open(latest_path, 'w')
-  print >> latest_file, set_version
-  latest_file.close()
+  osutils.WriteFile(latest_path, set_version, mode='w')
 
 
 def RemoveOldArchives(bot_archive_root, keep_max):
diff --git a/buildbot/cbuildbot_stages.py b/buildbot/cbuildbot_stages.py
index 06de066..a0d7417 100644
--- a/buildbot/cbuildbot_stages.py
+++ b/buildbot/cbuildbot_stages.py
@@ -1158,12 +1158,17 @@
   def _SetupArchivePath(self):
     """Create a fresh directory for archiving a build."""
     archive_path = self._GetArchivePath()
+
     if not archive_path:
       return None
 
     if self._options.buildbot:
       # Buildbot: Clear out any leftover build artifacts, if present.
       shutil.rmtree(archive_path, ignore_errors=True)
+    else:
+      # Clear the list of uploaded file if it exists
+      osutils.SafeUnlink(os.path.join(archive_path,
+                                      commands._UPLOADED_LIST_FILENAME))
 
     os.makedirs(archive_path)
 
@@ -1335,7 +1340,8 @@
 
     def UploadArtifact(filename):
       """Upload generated artifact to Google Storage."""
-      commands.UploadArchivedFile(archive_path, upload_url, filename, debug)
+      commands.UploadArchivedFile(archive_path, upload_url, filename, debug,
+                                  update_list=True)
 
     def ArchiveArtifactsForHWTesting(num_upload_processes=6):
       """Archives artifacts required for HWTest stage."""