You know android devices have a GNU kernel? If you DD the device, there's a kernel waiting for instruction. I'm constantly dumbfounded that these would be mass produced and released to the public by (them).
They really are stupid.
I spent about 100 bucks and a couple months taking apart android devices and messing with them, making homemade raspberry pies and portable VPNs that I could leave places. It was a lot of fun just messing with them, seeing what overlays I could write on the hardware. If you're into cheap thrills, I suggest buying a few old models and taking them apart. Once you do, there's 1000 threads to start pulling on.
A book for anyone that might be interested.
Truth
You're going to have a lot of fun. You'll need some base PHP but nothing that can't be learned on the fly.
Enjoy