[Q] Can i install a system app from one phone as user app on another?

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http://forum.xda-developers.com – Okay so i have this really old phone (Samsung Captivate) with a really awesoem clock app. But its a system app and i want to install it on one of my other phones (Galaxy Nexus) as a user app. They both are NOT running stock ROM. In fact the Cappy is on 4.2.1 and the Nexus on 4.2.2. Not a big differnece, right? So i presume this would be possible. Before you ask, i did do research on this and found nothing but moving one user app from one phone to another phone as a user app, etc. Nothing with moving a system app from one phone to user app on another. If you want i can upload the (HowTos)