diff --git a/tools/releasetools/check_target_files_signatures.py b/tools/releasetools/check_target_files_signatures.py
index 3048488..f9aa4fa 100755
--- a/tools/releasetools/check_target_files_signatures.py
+++ b/tools/releasetools/check_target_files_signatures.py
@@ -235,7 +235,7 @@
     self.certmap = None
 
   def LoadZipFile(self, filename):
-    d, z = common.UnzipTemp(filename, '*.apk')
+    d, z = common.UnzipTemp(filename, ['*.apk'])
     try:
       self.apks = {}
       self.apks_by_basename = {}
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index f174747..2b97518 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -564,7 +564,7 @@
   def unzip_to_dir(filename, dirname):
     cmd = ["unzip", "-o", "-q", filename, "-d", dirname]
     if pattern is not None:
-      cmd.append(pattern)
+      cmd.extend(pattern)
     p = Run(cmd, stdout=subprocess.PIPE)
     p.communicate()
     if p.returncode != 0:
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index be01a6d..f6b60ad 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -184,6 +184,8 @@
 OPTIONS.payload_signer_args = []
 
 METADATA_NAME = 'META-INF/com/android/metadata'
+UNZIP_PATTERN = ['IMAGES/*', 'META/*']
+
 
 def MostPopularKey(d, default):
   """Given a dict, return the key corresponding to the largest
@@ -2214,7 +2216,8 @@
     OPTIONS.extra_script = open(OPTIONS.extra_script).read()
 
   print("unzipping target target-files...")
-  OPTIONS.input_tmp, input_zip = common.UnzipTemp(args[0])
+  OPTIONS.input_tmp, input_zip = common.UnzipTemp(
+      args[0], UNZIP_PATTERN if OPTIONS.block_based else None)
 
   OPTIONS.target_tmp = OPTIONS.input_tmp
   OPTIONS.info_dict = common.LoadInfoDict(input_zip, OPTIONS.target_tmp)
@@ -2282,7 +2285,8 @@
   else:
     print("unzipping source target-files...")
     OPTIONS.source_tmp, source_zip = common.UnzipTemp(
-        OPTIONS.incremental_source)
+        OPTIONS.incremental_source,
+        UNZIP_PATTERN if OPTIONS.block_based else None)
     OPTIONS.target_info_dict = OPTIONS.info_dict
     OPTIONS.source_info_dict = common.LoadInfoDict(source_zip,
                                                    OPTIONS.source_tmp)