I've rooted my worlds-lowest-end-tablet the Azpen A727 successfully a while back. In my quest to recover as much of its tiny memory as possible, I came across a folder called /system/preinstall which has several .apks in it, for software that came with the tablet, that I don't want, and have uninstalled.
When I try to delete them using ES File Explorer, the app successfully gains root, but I get a message "[filename].apk cannot be deleted".
Is there a power greater than root?