First install Ubuntu 14.04.3 LTS. Download 'ubuntu-14.04.3-desktop-amd64.iso' from http://releases.ubuntu.com/trusty/ and install from USB using 'dd' (or 'Rufus' on Windows).

Wifi will be missing. So upgrade the Linux kernel to 4.1 or greater. I suggest using the kernel issued with Ubuntu 15.10 Beta 1 (or later) by downloading the following files from http://mirrors.kernel.org/ubuntu/pool/main/l/linux/ using 'wget':

linux-headers-4.1.0-3_4.1.0-3.3_all.deb

linux-headers-4.1.0-3-generic_4.1.0-3.3_amd64.deb

linux-image-4.1.0-3-generic_4.1.0-3.3_amd64.deb

linux-image-extra-4.1.0-3-generic_4.1.0-3.3_amd64.deb

and this file from http://mirrors.kernel.org/ubuntu/pool/main/l/linux-signed/ again using 'wget':

linux-signed-image-4.1.0-3-generic_4.1.0-3.3_amd64.deb

Install by entering:

dpkg -i *.deb

Now reboot and then update and upgrade all packages to the latest release:

apt-get update

apt-get upgrade