Change system app permissions through ADB I`m new in the Android world and have my first problem.
I have try to change the default launcher on my android tv stick (mk808b Android 4.4.1). And now the problem.

I have set the permissions with es file explorer to read and write on the old launcher to back him up and copy the new one to replace the old.

After that I have pushed the home button to start the new launcher but all I get is a black screen with the upper controll elements.

How I get this Launcher running?
I think I have to set the permissions to the new launcher but have a black screen!
ADB Works but I dont now how to set the permissions to my launcher.apk or to read out the name of the apk to chamge chmod!?

Thanks a lot
I have managed it I only use

adb shell am start -n com.estrongs.android.pop/.view.FileExplorerActivity


to start my explorer apk. 
Now I was able to do it my default UI.