Early last year, I found articles on two separate projects that were both
working on making completely free software versions of Android OS. I'm
having a hard time finding the articles now, but as soon as I do, I will post
it.
On a side note, for those wanting to root your android
A FOSS app repository
http://f-droid.org/
is not what you're looking for, but, maybe it will be useful when you need
install something.
CyanogenMod includes the proprietary drivers while Replicant doesn't. Either
way neither is really free as the modem can access the CPU on most phones and
spy on the user (e.g. remotely turn on the microphone and record the user). A
few phones do not provide the modem access to the CPU (e.g.
