Comment 28 for bug 139832

Another way to solve this bug:

 sudo apt-get update
    sudo apt-get install build-essential linux-headers-$(uname -r)
    cd ~
    mkdir ~/rt61
    cd ~/rt61
    wget http://rt2x00.serialmonkey.com/rt61-cvs-daily.tar.gz
    tar -zxvf rt61-cvs-daily.tar.gz
    cd rt61-cvs*/Module
    make

    sudo ifconfig wlan0 down
    sudo modprobe -r rt61pci
    echo 'blacklist rt61pci' | sudo tee -a /etc/modprobe.d/blacklist

    sudo make install
    echo 'rt61' | sudo tee -a /etc/modules

And Edit the right parameters for your connexion

    sudo gedit /etc/network/interfaces