Lollipop 5.1.1 based device. OLD ES File Manager installed. (Yes, the exploitable one). I can copy to/from the device. I tried Kingo Root, Root Genius, Towel root, etc. None of those work. "7 taps" doesn't enable Developer mode, nor does 10, 20, or 100. I can't install a new image, and the device doesn't have volume buttons, so I can't get to recovery. Does anyone know what I need to do to enable adb?
The device is ROCKCHIP based. That being the case, there are PLENTY of tools that will allow you to dump the device ROM, then you can pick through it, and won't actually NEED adb.
rkDumper is a very good one. Get it here: rkDumper