fix length is null

Change-Id: I781e9efce5f74a3e5eb32de6dda8025b78615336
fix download error

Change-Id: I49e3c6096a2ce9f6466c4ef518f064b87d0f1993
fix version display error

Change-Id: I53676caa0a6b7bb8ecbb4f01b866f0f751847b9f