diff --git a/core/build_id.mk b/core/build_id.mk
index 0107506..0e8e2cf 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,4 +18,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-export BUILD_ID=MDA65H
+export BUILD_ID=MASTER
diff --git a/tools/releasetools/edify_generator.py b/tools/releasetools/edify_generator.py
index 566e687..a52e328 100644
--- a/tools/releasetools/edify_generator.py
+++ b/tools/releasetools/edify_generator.py
@@ -243,6 +243,15 @@
     cmd = "delete(" + ",\0".join(['"%s"' % (i,) for i in file_list]) + ");"
     self.script.append(self.WordWrap(cmd))
 
+  def DeleteFilesIfNotMatching(self, file_list):
+    """Delete the file in file_list if not matching the checksum."""
+    if not file_list:
+      return
+    for name, sha1 in file_list:
+      cmd = ('sha1_check(read_file("{name}"), "{sha1}") || '
+             'delete("{name}");'.format(name=name, sha1=sha1))
+      self.script.append(self.WordWrap(cmd))
+
   def RenameFile(self, srcfile, tgtfile):
     """Moves a file from one location to another."""
     if self.info.get("update_rename_support", False):
@@ -254,7 +263,7 @@
     """Prepend an action with an apply_patch_check in order to
        skip the action if the file exists.  Used when a patch
        is later renamed."""
-    cmd = ('sha1_check(read_file("%s"), %s) || ' % (tgtfile, tgtsha1))
+    cmd = ('sha1_check(read_file("%s"), %s) ||' % (tgtfile, tgtsha1))
     self.script.append(self.WordWrap(cmd))
 
   def ApplyPatch(self, srcfile, tgtfile, tgtsize, tgtsha1, *patchpairs):
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 3a69675..25e3724 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -1391,11 +1391,36 @@
   # Delete all the symlinks in source that aren't in target.  This
   # needs to happen before verbatim files are unpacked, in case a
   # symlink in the source is replaced by a real file in the target.
-  to_delete = []
+
+  # If a symlink in the source will be replaced by a regular file, we cannot
+  # delete the symlink/file in case the package gets applied again. For such
+  # a symlink, we prepend a sha1_check() to detect if it has been updated.
+  # (Bug: 23646151)
+  replaced_symlinks = dict()
+  if system_diff:
+    for i in system_diff.verbatim_targets:
+      replaced_symlinks["/%s" % (i[0],)] = i[2]
+  if vendor_diff:
+    for i in vendor_diff.verbatim_targets:
+      replaced_symlinks["/%s" % (i[0],)] = i[2]
+
+  if system_diff:
+    for tf in system_diff.renames.values():
+      replaced_symlinks["/%s" % (tf.name,)] = tf.sha1
+  if vendor_diff:
+    for tf in vendor_diff.renames.values():
+      replaced_symlinks["/%s" % (tf.name,)] = tf.sha1
+
+  always_delete = []
+  may_delete = []
   for dest, link in source_symlinks:
     if link not in target_symlinks_d:
-      to_delete.append(link)
-  script.DeleteFiles(to_delete)
+      if link in replaced_symlinks:
+        may_delete.append((link, replaced_symlinks[link]))
+      else:
+        always_delete.append(link)
+  script.DeleteFiles(always_delete)
+  script.DeleteFilesIfNotMatching(may_delete)
 
   if system_diff.verbatim_targets:
     script.Print("Unpacking new system files...")