The steps are the follwoing:
Good news the AMD/ATI RV730XT (Radeon HD4670) is recognised from Ubuntu 14.04.1 TLS.
In any case the steps are ther following:
The uninstall script in the first command will only exist if you downloaded the drivers and installed them directly (rather than building packages as this guide does). Skip the first command if it does not exist.
sudo sh /usr/share/ati/fglrx-uninstall.sh
sudo apt-get remove --purge fglrx fglrx_* fglrx-amdcccle* fglrx-dev*
If you plan on using open-source drivers, you will need to reinstall some packages because Catalyst overwrites or diverts some key 3D libraries with proprietary versions. For more information on this issue, see this Ubuntu wiki page
sudo apt-get remove --purge xserver-xorg-video-ati xserver-xorg-video-radeon
sudo apt-get install xserver-xorg-video-ati
sudo apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri xserver-xorg-core
sudo mv /etc/X11/xorg.conf /etc/X11/xorg.conf.backup
sudo rm -rf /etc/ati
If you receive $ E: Internal Error, No file name for libgl1-mesa-dri Change the third command above to: sudo apt-get install --reinstall libgl1-mesa-glx:i386 libgl1-mesa-glx:amd64 libgl1-mesa-dri:i386 libgl1-mesa-dri:amd64 xserver-xorg-core
After you finished all, reboot, then install the legacy 12.6 Driver, following the same procedure in the same Wiki:http://wiki.cchtml.com/index.php/Ubuntu_Precise_Installation_Guide#Installing_Catalyst_Manually_.28from_AMD.2FATI.27s_site.29
Start from "Before you start" section, and skip the "wget" download, instead use the 12.6 Legacy you have downloaded. All the rest the same. It will eventually work !
After you installed, do not forget to:
sudo amdconfig --initial -f
