1. I would recommend older version of apktool as it would work faster on your tab.
2. Install busybox if its not already installed.
3. If you are replacing a png, then keep in mind that you must replace those pngs with "SAME NAME" as they were before in the SystemUI.
4. Donot touch .9.pngs if you don't know how to play with them.
I already know how to replace pngs inside an apk,and I know that .9.PNG are not. png. But what I can't do is to successfully compile and sign the app after adding-not just replacing-new files to the existing ones inside_let's say package/res/drawable_apk.