diff --git a/tools/pbpack.py b/tools/pbpack.py
index 7bee6f413..32f78ac70 100755
--- a/tools/pbpack.py
+++ b/tools/pbpack.py
@@ -249,7 +249,7 @@ def dump(self):
         for i, entry in enumerate(self.table_entries, start=1):
             print('  %u: Offset %u Length %u CRC 0x%x' % (i, entry.offset, entry.length, entry.crc))
 
-    def __init__(self, is_system):
+    def __init__(self, is_system=True):
         self.table_size = 512 if is_system else 256
         self.content_start = self.MANIFEST_SIZE_BYTES + self.table_size * self.TABLE_ENTRY_SIZE_BYTES
 
diff --git a/tools/unpack.py b/tools/unpack.py
index c666e5fc6..4724732f4 100644
--- a/tools/unpack.py
+++ b/tools/unpack.py
@@ -21,11 +21,15 @@
 def main():
     parser = argparse.ArgumentParser(description=
         'Unpack pbpacked data to recover original file content.')
+    
     parser.add_argument('pbpack', type=str, help='app_resources.pbpack file to unpack')
+    parser.add_argument('--app', default=False, action='store_true',
+                        help='Indicate this pbpack is an app pbpack')
+    
     args = parser.parse_args()
 
     if os.path.exists(args.pbpack):
-        resource_pack = ResourcePack().deserialize(open(args.pbpack,'rb'))
+        resource_pack = ResourcePack().deserialize(open(args.pbpack,'rb'), is_system=not args.app)
         for idx, resource_data in enumerate(resource_pack.contents):
             with open(str(idx) + '.dat','wb') as outfile: 
                 outfile.write(resource_data)