I previously had this tutorial for Ubuntu 12.10 on a Padfone and a Nexus 10. I’ve updated it for Ubuntu 14.04.
In this guide, I used http://ports.ubuntu.com/ubuntu as the repository for the bootstrap. However, I ran into some problems and had to retry the installation several times, and ports.ubuntu.com was somewhat slow for me, so I mirrored the trusty armhf repository at http://jtpool.tan-ce.com/ubuntu. I give no guaranties about its uptime or freshness, but if you’re near me (Singapore), you could give it a try to speed things up.
In general, Ubuntu 14.04 doesn’t install as cleanly as 12.10 did, but I believe it should still work. In future, I may have to switch to another distro. Perhaps Arch.
This tutorial documents the steps I went through to get a working Ubuntu system (with LXDE) on my Android device, a Nexus 10. I decided to use the ARM hard-float port (armhf) instead of armle in order to try to extract better performance from the processor.
The tutorial was written based on the notes I made during the process. This tutorial is not for the faint of heart, and it’s best if you have some familiarity with Linux and aren’t afraid of the terminal. I’m not sure if I missed our anything in my notes, so let me know in the comments if anything doesn’t work.
Also, I believe there’s an app that does exactly what I’m trying to do here, but I don’t know if it supports the Padfone yet. If you’re not so comfortable with the terminal, this is probably the way to go.
The following were webpages that I found useful. Some even have almost all the steps you need to do this.
- A rooted tablet
- Terminal Emulator – I like this app because the hardware keyboard on the Padfone dock functions like a PC keyboard, with the back button functioning as escape. Very useful, especially when using Vim.
- At least 2GB of space on your SD card or internal storage. (Following this tutorial exactly will use 3.5GB)
- An Linux environment (Might work even on a live CD)
You will also likely need busybox on your tablet
Part 1 – Creating the bootstrap image
We are going to create a filesystem image to contain the entire Ubuntu installation. Then we will copy it to the Padfone.
On your Linux desktop (or server!) ensure you have debootstrap installed:
sudo apt-get install debootstrap
Change directory to a partition with enough space. (3.5G in this tutorial, 2GB minimum) For example:
Create the empty disk image file:
dd if=/dev/zero of=img.lubuntu-armhf.root bs=8k count=458752 sudo mkfs.ext4 -L chroot -c img.lubuntu-armhf.root sudo tune2fs -c 0 img.lubuntu-armhf.root
This creates a 3.5GB filesystem. If you want something smaller, like 2GB, substitute 458752 with 262144. Bear in mind that if you make your filesystem only 2GB, you’ll only have about 200MB free after installing the Lubuntu GUI.
Now, loop mount the newly created filesystem:
mkdir chroot sudo mount -o loop img.lubuntu-armhf.root chroot
Now begin downloading the core system files.
sudo debootstrap --arch armhf --foreign trusty chroot http://ports.ubuntu.com/
Take a break while it downloads the core files. Once that is done, unmount the filesystem:
cd ../../ sudo umount chroot
Then copy img.lubuntu-armhf.root to your phone.
Part 2 – Setting up the system
Now that we have the bootstrapped filesystem on the phone, we’re going to set it up and install some software packages.
First, open Terminal Emulator, become root, and navigate to the where the image is. For me, my image was in /sdcard/lubuntu
su cd /sdcard/lubuntu
Now, mount the filesystem, setup a minimal environment, and chroot into it. You will need busybox in order to chroot. In my tablet, busybox is installed in /system/bin-busybox.
export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/system/bin-busybox" export TERM=linux export HOME=/root export USER=root export UID=0 mount -o loop img.lubuntu-armhf.root lubuntu mount -t proc proc lubuntu/proc mount -t sysfs sysfs lubuntu/sys mkdir lubuntu/dev/pts mount -t devpts devpts lubuntu/dev/pts chroot lubuntu /bin/bash
Now that we’re in, let’s finish up the installation:
You’ll notice that a package failed to install – that’s udev. udev in Ubuntu 14.04 performs several checks and will fail, causing apt to fail to install the entire package. To neuter udev so that we can install the rest of the system, run the following command:
dpkg-divert --local --rename --add /etc/init.d/udev cp /etc/init.d/udev.distrib /etc/init.d/udev
Now, open /etc/init.d/udev in vi, and right after “### END INIT INFO“, enter this line:
We also need to neuter initctl so that the fact that upstart doesn’t work does not give us lots of warnings and failures.
dpkg-divert --local --rename --add /sbin/initctl cp /bin/true /sbin/initctl
Now do some additional basic configuration. (These settings are for my locale, which is English, Singapore. Modify the commands as necessary to match your actual locale.)
locale-gen en_SG en_SG.UTF-8 dpkg-reconfigure tzdata
Set the hostname and DNS server:
echo localhost > /etc/hostname echo 'nameserver 126.96.36.199' > /etc/resolv.conf
Next, open /etc/apt/sources.list in an editor and replace the contents with this:
deb http://ports.ubuntu.com/ trusty main universe multiverse restricted deb http://ports.ubuntu.com/ trusty-updates main universe multiverse restricted deb http://ports.ubuntu.com/ trusty-security main universe multiverse restricted
Now we’ll update the apt indexes, upgrade to the latest versions of all the packages, and finish installing the packages that failed to install during the debootstrap.
apt-get update && apt-get upgrade -y
Ok, let’s get the rest of the software. These are all optional, of course, but I like to have SSH, vim and tmux.
apt-get install ubuntu-standard vim tmux openssh-client openssh-server apt-get clean rm /var/run/reboot-required*
If you followed me and installed ubuntu-standard, you’d get another failed package: libpam-systemd. To solve this problem, we’re going to create a dummy init.d script. Create a file at /etc/init.d/systemd-logind with 0755 permissions (executable by all). In this file, enter the following:
#!/bin/sh exit 0
Then, let apt complete the installation by running “apt-get upgrade -y”.
Ok, now let’s create a non-root user and disable the root password. Of course, replace jack with a user name of your choosing.
passwd -l root adduser jack usermod -a -G sudo jack
On Android, users which aren’t part of the AID_INET group (Group ID 3003) will not be able to use IP sockets at all. To get around this problem, we’ll create a group called aid_inet in the chroot with the correct group ID and make the non-root user (“jack”) a member of this group.
groupadd --gid 3003 aid_inet usermod -a -G aid_inet jack
One last thing, it’s convenient to have a script to be able to get into the chroot quickly. Create a file called enter_chrootand place the following script in it:
#!/system/bin/sh PREFIX=/Removable/MicroSD ROOTFS=$PREFIX/lubuntu if [ ! -d $ROOTFS/etc ]; then echo "Mounting lubuntu chroot..." mount -o loop $PREFIX/img.lubuntu-armhf.root $ROOTFS mount -t proc proc $ROOTFS/proc mount -t sysfs sysfs $ROOTFS/sys mount -t devpts devpts $ROOTFS/dev/pts mount --bind /sdcard $ROOTFS/mnt/sdcard mount --bind $PREFIX $ROOTFS/mnt/MicroSD fi echo "Setting environment vars" export TERM=linux export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" export USER=jack export SHELL=/bin/bash export HOME=/root export LANG=C echo "Starting shell as user $USER" /system/bin/chroot $ROOTFS sudo -u $USER -i
This script mounts the filesystems (if they haven’t been mounted) sets up the environment, then enters the chroot properly. Now, to enter the chroot:
The “sh” is necessary because files are not allowed to be executable on the sdcard.
Ok, the command line environment is all done!
Part 3 – Setting up a desktop environment
There are two ways to run a GUI from inside the chroot. Previously, I ran an X11 server in a framebuffer and then used VNC to access it. However, there is now a pretty good X11 server available for Android. I generally use this app. Then all you need to do is install the app, install the “lxde” metapackage, and run “DISPLAY=:0 startlxde”, assuming the app started on display :0.
Note: When I installed lxde, it re-installed libpam-systemd, and two more packages failed. When I purged it (again), those two packages were uninstalled along with it.
That said, if you’re still interested in the VNC on X framebuffer method, take a look at the old article.