This page describes different Android projects related and supported by tinkerphones
Replicant is a fully free Android distribution running on several devices. It is a free software project. This Android distribution is the most advanced for the GTA04, please refer to our gta04-replicant project: http://projects.goldelico.com/p/gta04-replicant
Also, the upstream Replicant project is working on official support for the GTA04:
CyanogenMod is an aftermarket firmware for a number of cell phones based on the open-source Android operating system. It offers features not found in the official Android based firmwares of vendors of these cell phones.
Port of the Andoid OS to the Openmoko Freerunner (does not work on GTA04)