Thanks for the info. Yup installing 6.4 SP1 resolve my problem.

I'm working on AEM Screen right now. Problem I encounter is, mis-align firmware version on my client device and aem server. On my device dashboard, I see my device is with firmware 2.3.2, while in Action column is 2.2.214.  My AEM Screens player on device is downloaded from google play at newest ver...