Madwifi has put out a super good fix for this device.
Here is how to get it working:
NOTE: Make sure you have disabled the Atheros Chipset driver in the Hardware Manager already and rebooted. (System > Administration > Hardware Drivers)
1. Download this file: CLICK HERE
Once it is downloaded right-click on it and extract it.
2. Make sure you have build-essentials installed. If you are not sure you should open a Terminal (Applications > Accessories > Terminal) and enter this command:
sudo apt-get install build-essentials
Also install the linux-headers with this command:
sudo apt-get install linux-headers-$(uname -r)
3. Now turn off all your wireless devices in the Terminal with these commands:
ifconfig ath0 down
ifconfig wifi0 down
If you get a message telling you the device is not found or something, that’s ok.
4. In the Terminal navigate to the folder you extracted from the file you downloaded earlier. Mine was on the Desktop so I entered this in the Terminal to get inside:
cd Desktop/madwifi-hal-0.10.5.6/madwifi-hal-0.10.5.6-r3875-20081105/
Now do the following to enter the scripts folder:
cd scripts
Now to remove the old modules from the system and its memory:
./madwifi-unload
./find-madwifi-modules.sh $(uname -r)
cd ..
5. Now to compile the new madwifi driver. Simple type make into the Terminal and wait for it to finish.
When its done make sure there were no errors in the output.
Now type in sudo make install to install the driver.
6. And finally load the module with:
sudo modprobe ath_pci
And to make the module load with startup we need to edit a file, so do this in the Terminal:
sudo gedit /etc/modules
Add this line to the end.
ath_pci
Then save and close the file.
If the wireless is not working just reboot your computer.
Your Done!