Blocked Android Multimedia system I bought Android Multimedia system for my car:
Model: MGCOL1
Ver: 4.4.2
Ver: MPSS.TR.1.0-01780-M8626AAAAANAZM
Core Ver: 3.4.0 - fengxunyi@fly-server-24core #1
Build: msm8226-userdebug 4.4.2 KVT49L eng.fengxunyi.20150828.144551 test-keys  

But is seems that the Android is blocked: no file explorer, no browser (but there is an app with WebView with Google), no Google Play Store and no Developer options for adb (I have tried to click on the Build Number and nothing happened).

How can I unblock it? I want to install some apps but I don't know how.
You can push apk files to this device trough Bluetooth. Pair it with your smartphone and choose except all file types in the car system bluetooth. Of course don't forget to Check Install from Unknown sources in the car system too.