I want to take an (older) Android device and replace the Android system.
I understand that I will need to a) get root access to it, and b) install a new system image (ROM&kernel). I also suspect that's a simplification.
My problem is that I'm having great difficulty knowing where to start. I have found lots of disparate bits of information on small aspects of this, but much of it seems to start either with "magic" software on windows, or at some point arbitrarily far downstream, but I don't know how far, and I don't know how to get there. It probably doesn't help that I'm trying to learn this using an old "I don't care if I destroy this" phone (LG Optimus 670)
I am a long-time programmer and Linux user, so I'm comfortable with technical instructions provided they're accurate and don't use new terminology without explaining it, and I'm even happier with an explanation of how the parts of a system fit together, and the tools that interact with it, from which I might extrapolate what to do, or why something hasn't worked.
Unfortunately, while I go to the point that I can use adb to get to a shell on my device, it's not a root shell, and anything I try to do (beyond simple "ls" or "ps" anyway) is generally met with a permission problem.
Partly perhaps because I run Linux, not windows, I've totally failed to find a way to root my device (it's an old LG Optimus 670 with a ZDJ "baseband"--what's that, btw, I thought baseband was a term referring to a way of using a medium to carry a single signal, as distinct from broadband, meaning you can encode multiple signals onto it! Perhaps this relates to the software controlling this behavior?)
I've also read that the ZDJ must be downgraded to ZDM before rooting, but I don't know where to begin doing that either.
So, can anyone suggest a good resource that might explain the fundamental structure of an Android system, so I can begin to get a better grip on it? And, can anyone tell me if there are resources that will help me hack this system using Linux as my host, rather than windows? (Or, if I just have to have windows, I suppose that's worth knowing, I could probably bring up a virtual machine if I must!)