[Nexus One Android Development] jairuncaloth:
Booting Debian with X11 on the Google NexusOne

This howto can also be found on my blog.

http://www.irregular-expression.com/?p=30

Screenshots here

http://picasaweb.google.com/JairunCaloth/Debian?feat=directlink

This is a method to boot into Debian via fastboot on the nexus one from

your SD-card. This is NOT a chroot Debian image, it is honest to goodness

Debian running directly on the hardware. This is completely non destructive to

the android OS. Connectivity to the device can be provided by adbd, ssh, or

serial console. Wifi works perfectly. I have not tested bluetooth. Touchscreen

works, but needs tweaking. X11 works in framebuffer using the Debian

testing branch (squeeze). In order to get a full fledged X driver with

3D acceleration we'll need the driver from

https://www.codeaurora.org/index.php?xwinp which I haven't been able to get

to build. This doesn't mean it's broken. It just means I suck

at cross compiling ;).

Todo:

-Tweak settings to make X more usable.

-Find out how to use the soft keys.

-Get the CodeAurora MSM/QSD X driver working.

-Find decent method to input text.

-Test bluetooth

-Look into using the GSM radio.

-Audio

-Figure out how to configure adbd.

-Get someone who knows C and wants to hack on the recovery image to enable booting debian from there.

This how-to pulls heavily from the debian-arm install guide.

http://www.debian.org/releases/stable/arm/index.html.en

Requirements:

adb (android-sdk)

fastboot

chroot (on your phone)

sdcard with room for Debian - 2gigs seems to be sufficient for Debian + xfce.

I Had about a gig leftover. For this guide, I'm starting fresh with a 4GB sdcard

that I'm devoting completely to Debian. According to the Debian install guide,

you need at least 32MB of memory and 500MB of hard disk space. The guide

recommends at least 5GB of storage for a comfortable install. But since I'm

using the lighter XFCE4 desktop I haven't had any space issues.

http://www.debian.org/releases/stable/arm/ch03s04.html.en

1. Re size the SD card

(don't forget to backup your data before you go messing with partition tables!!)

(optional) Instead of using a partition on your main SD card, you could

simply use another sdcard and dedicate the entire thing to Debian.

Note: android didn't like me very much when I did this. I put in a

tiny (30MB) vfat partition right at the beginning of the blank sdcard

I mounted the sdcard on my Ubuntu system and used gparted to break

off 2 gigs to use for Debian. Make sure you keep the normal android

sdcard partition as the first partition otherwise android

will not be able to find it.

If you're using apps to SD or anything else like that. Debian should

probably have the last partition. I'm not 100% sure on this since I

don't use my sdcard for anything else.

2. Format the new partition.

ext2 is probably best. (least abusive on the sdcard. ext3 & 4 have

journaling which may be bad for the life of your sdcard)

I used Gparted for this part as well.

3. If you are installing from an Ubuntu or Debian desktop, install debootstrap

$ sudo apt-get install debootstrap

Users of other distros may be able to get debootstrap but I'm not sure.

4. Mount the sdcard on your desktop.

anywhere will do just remember where you put it :-p

ex.

$ mount /dev/sde2 /mnt/android

5. debootstrap

run debootstrap

you can change to a mirror closer to you if you don't want to use the

US mirror - http://www.debian.org/misc/README.mirrors

I'm using the Debian testing release (squeeze). I had issues getting

X11 running in lenny, and have not tested sid.

(lenny is stable, squeeze is testing, and sid is unstable)

http://www.debian.org/releases/

debootstrap --arch armel --foreign <release> </path/to/debian> <mirror>

ex:

# debootstrap --arch armel --foreign squeeze /mnt/android http://ftp.us.debian.org/debian

6. debootstrap(part2)

Unmount the sdcard from your desktop.

Reboot the phone here since you've been mucking with the sdcard

file system. Android didn't like my sdcard until I did.

$ adb shell

mount the sdcard somewhere on the android file system.

look in /dev/block for the sdcard.

Typically mmcblk0p# where # is the partition number.

*note* the directory I use to mount mine does not exist under normal android.

If this is your first time you will need to create the directory.

mkdir -p /data/local/mnt

ex.

# mount -t ext2 /dev/block/mmcblk0p2 /data/local/mnt

chroot/debootstrap

# export PATH=/usr/bin:/usr/sbin:/bin:$PATH
# chroot /data/local/mnt/ /debootstrap/debootstrap --second-stage

this will take a while especially if you have a slower sdcard.

6. While that's working, now is a good time to get to work on your kernel

I used the open source android kernel 2.6.29

http://android.git.kernel.org/

Started with mahimahi_defconfig and starting customizing from there.

Things to note.

- file systems - don't forget to add support for whatever file systems

you need. Your root file system support cannot be built as a module.

- wireless driver config - You may want to change the location the

kernel looks for your wifi firmware (this is different from the

kernel module).

I stuck mine in /etc/firmware, default is /system/etc/firmware.

If you don't change this, you will have to put the firmware

in /system/etc/firmware

- wireless - Add in support for standard wifi extensions.

- networking - standard tcp/ip stuff... iptables if you want ect...

- I wasn't able to get the kernel to boot into Debian until I turned

off initramfs support.

(note. this was before I discovered the 'noinitrd' kernel

kernel cmdline option. So disabling initrd may not be required)

- If for some reason you are using ext4, it will fail to mount unless

you add in large devices and files support

- Default kernel command string - has no effect.

This gets overwritten when you boot with fastboot or make a boot.img

- Drivers - I left all the normal android drivers in.

-Changed the firmware path for wifi.

-Added in support for virtual terminal under character devices

-Enabled MSM serial support (if you don't have a serial cable

this is useless to you)

-You can build the wifi driver into the kernel if you want.

Link to the kernel config I used. Use at your own risk.

It works for me but I can't promise it's perfect or even good.

http://irregular-expression.com/tmp/config

I would love input on building a better kernel config.

If you don't want to build your own kernel, feel free to use mine http://irregular-expression.com/tmp/zImage

7. Chroot and configure Debian.

There are still some things that need configuring before we reboot into

Debian. Since fbconsole does not appear to be working, if you don't

have a serial cable you will be flying blind until Debian is fully

booted and you can connect with ssh. Since there are still things to do

before we reboot, we're going to chroot into Debian just like if we are

using a Debian chroot image.

For more information and examples of config files.

http://www.debian.org/releases/stable/arm/apds03.html.en

It's probably best to use wifi for your data on the phone for this.

If you're on Linux and connected to the same router as the phone, copy

over your resolv.conf

$ adb push /etc/resolv.conf /data/local/mnt/etc/resolv.conf

If you are not in Linux or are not connected to wifi you will need to

set up resolv.conf with something sane.

ex. from jay freeman's original Debian chroot.

$ echo 'nameserver 4.2.2.2' > /data/local/mnt/etc/resolv.conf

push wifi driver to the device

First we need to create a couple directories. Log into the phone with adb shell

$ adb shell
# mkdir -p /data/local/mnt/etc/firmware
# mkdir -p /data/local/mnt/lib/modules/2.6.29-droid-debian/kernel/drivers/bcm4329
# exit

Upload wifi kernel module and firmware. If you're using my prebuilt kernel, grab this one. http://irregular-expression.com/tmp/bcm4329.ko

$ adb push <kernelroot>/drivers/net/wireless/bcm4329/bcm4329.ko /data/local/mnt/lib/modules/2.6.29-droid-debian/kernel/drivers/bcm4329/

copy /system/etc/firmware/fw_bcm4329.bin to wherever you

specified in the kernel config.

# cp /system/etc/firmware/fw_bcm4329.bin /data/local/mnt/etc/firmware/

Setup environment variables, copy over adbd, and other stuff needed to

make things work. This should all be run from within an adb shell

# cp /sbin/adbd /data/local/mnt/sbin/adbd
# sysctl -w net.ipv4.ip_forward=1
# export PATH=/usr/bin:/usr/sbin:/bin:$PATH
# export TERM=linux
# export HOME=/root

Next chroot and setup mount points

# chroot /data/local/mnt /bin/bash
# mount -t devpts devpts /dev/pts
# mount -t proc proc /proc
# mount -t sysfs sysfs /sys

Welcome to Debian chroot that we all know and love.

Lets finish configuring this thing.

Configure adbd to run on boot and create a symlink so adbd can find bash.

Edit /etc/rc.local. Add adbd before exit 0

#add this to /etc/rc.local

/sbin/adbd &

# mkdir -p /system/bin/
# ln -s /bin/bash /system/bin/sh

Now we need to be able to install packages

don't forget if you are not using squeeze to change it here

# echo 'deb [url]http://ftp.us.debian.org/debian[/url] squeeze main' >> /etc/apt/sources.list
# apt-get update

You should see aptitude updating it's package list.

Install some needed packages

# apt-get install wpasupplicant wireless-tools udev ssh

Other packages

All up to your choice. Things like text editors, X, ect...

some suggested packages

# apt-get install locales vi

Wifi driver

When you try to load the wifi module, Linux will complain about not

being able to parse modprobe.d. To fix this run depmod. If it complains

a directory doesn't exist then create it.

# depmod -a

Edit /etc/modules and add the bcm4329 module

# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.
# Parameters can be specified after the module name.
bcm4329

Setup fstab - critical: don't forget to configure the root file system

or your system won't boot. If you like, mount your vfat sdcard partition

here too. Don't forget to mkdir for the mount point.

*note* after boot the memory card is located at /dev/mmcblk0p#.

Here is my /etc/fstab

# /etc/fstab: static file system information.
#
# file system mount point type options dump pass

/dev/mmcblk0p2 / ext2 defaults 1 1
proc /proc proc defaults 0 0
/dev/mmcblk0p1 /media/sdcard vfat defaults 0 0

configure network

These two files will be tuned to what you need.

Here are a couple examples.

/etc/network/interfaces

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp
wpa-driver wext
wpa-conf /etc/wpa_supplicant.conf

/etc/wpa_supplicant.conf

ctrl_interface=/var/run/wpa_supplicant

network={
ssid="myOpenNetwork"
scan_ssid=1
key_mgmt=NONE
}
network={
ssid="MyHomeNetwork"
scan_ssid=1
key_mgmt=WPA-PSK
psk="MyWifiPassword"
}
network={
ssid="MyFriendsWifi"
scan_ssid=1
key_mgmt=WPA-PSK
psk="MyFriendsWifiPassword"
}

SSH

If you want ssh to start on boot run this command.

*note* You will probably want to set a static IP address if you plan on accessing debian through ssh.

# update-rc.d ssh defaults

inittab

no need for getty so comment it out in /etc/inittab

if you have a serial cable, configure it here. something like this.

T0:23:respawn:/sbin/getty -L ttyMSM0 115200 linux

hostname

configure your system's hostname - you can set this to whatever you like

# echo DebianHostName > /etc/hostname

Set root password

# passwd

# useradd -m -G audio,dialout,floppy,video,staff username

Add user account

# useradd -m -G audio,dialout,floppy,video,staff yourusername -s /bin/bash
# passwd yourusername

8. Almost there!

Double check your configs and have your kernel handy.

The next step is to boot into Debian.

9. Boot Debian

put the device into fastboot mode

$ adb reboot bootloader

the '-c' flag specifies arguments to pass to the kernel for boot.

This is probably the bare minimum.

Format is "fastboot -c 'kernelcmdline' boot zImage"

$ fastboot -c 'root=/dev/mmcblk0p2 rw rootfs=ext2 init=/sbin/init rootwait noinitrd' boot zImage

Wait just a few minutes. DHCP is probably the longest part of this.

10. Connect via ADB.

If everything went well you should be able to log into the

phone via adb. adb push and pull work as well.

$ adb shell

11. Install X11

For a basic X11 install. This is probably not what you want.

# apt-get install xserver-xorg

You can install whatever window manager/desktop environment you like,

I used XFCE. Most window managers likely depend on xserver-xorg so it

will get pulled in when you install.

# apt-get install xfce4

After I installed xfce4 I was able to get X on the main display by

simply running startxfce4

# startxfce4

By default Debian is configured to only allow root to startx.

If you want to be able to run X as a user edit /etc/X11/Xwrapper.config

*note* even with this I haven't been able to run X as a normal user.

Only root.

Change

allowed_users=console

to

allowed_users=anybody

Currently touchscreen is a little weird. It feels almost like using a

laptop touchpad. The mouse moves much faster then your finger and tapping for

click isn't enabled by default but two finger tap will right click. You can

also move the mouse with the trackball. Clicking the trackball registers a

click. But you have to wiggle the trackball just a tiny bit after you click to

make it register. I am going to work on tweaking the fdi policy files to

make things a little more usable.

Text entry is a bit of a pain point currently. There are several on screen

keyboards out there. One interesting one I found is called cellwriter.

The touchscreen will need to be tweaked before it will work well with

onscreen keyboards.

For other ideas on window managers and other software check out this link

http://wiki.openmoko.org/wiki/Debian