Ubuntu – BQ Aquaris lock screen not working

I think this is indeed a reported bug. https://bugs.launchpad.net/today-scope/+bug/1439382

Create a chroot inside the home directory:

mkdir -p vivid-chroot
cd vivid-chroot
wget http://cdimage.ubuntu.com/ubuntu-touch/vivid/daily-preinstalled/current/vivid-preinstalled-touch-armhf.tar.gz
sudo tar -zxvf vivid-preinstalled-touch-armhf.tar.gz

Then, use the chroot and install whatever CLI tools you need to use, within that chroot:

cd ~/vivid-chroot
sudo chroot .
apt-get update
apt-get install git

In order to perform certain things, it may be required to bind mount some directories. You will need to take extra care when doing so, if you wish to delete the chroot from your phone, or perform other destructive actions.

sudo mount --bind /proc /home/phablet/vivid-chroot/proc
sudo mount --bind /dev /home/phablet/vivid-chroot/dev
sudo mount --bind /sys /home/phablet/vivid-chroot/sys

This isn't an exhaustive list, but you can bind mount other directories as needed in similar fashion. You need not create the chroot in your home directory if you have an external storage device to create it on, such as an SD card. However, not all phones have SD card slots. If you wish to create the chroot on an SD card, simply replace the home directory in the commands above, with the path to a directory on your alternate storage media where you wish to create the chroot.