diff --git a/uniflash.py b/uniflash.py
index 72656cd..4bc239c 100644
--- a/uniflash.py
+++ b/uniflash.py
@@ -28,6 +28,8 @@ def connect(vid, pid):
     dev.set_configuration()
     cfg = dev.get_active_configuration()
     intf = cfg[(0,0)]
+    global bSize
+    bSize = intf[0].wMaxPacketSize
     epIn = usb.util.find_descriptor(
         intf,
         custom_match = \