I was able to install astro file manager via apk. I had to allow outside sites. I usd the package manager when prompted and open after install. I was able to see the system files but i tried to copy them to my sd card with no luck. This does not create a link on the shelf and i dont know how to launch it unless i reinstall from the downloads in the browser. I also attempted other apk some worked others did not. Not sure if this helps anyone I m not a developer just fooling around at Mc donalds playing with my new nook tablet. Maybe this info is already out their if so im sorry.