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udev
Udev is the tool used to populate your /dev directory. This tool is important for your system to be able to "interact" with underlying hardware, and is required for instance to detect hard drive, usb keys, ... Obviously, it is needed to launch any linux distribution you would like to have !

This Howto is the sequel of Framebuffer console tutorial on this wiki. It is assumed you managed to get a working framebuffer console.

Step 1 : get all the udev related files
For this, we will use the image provided by linux4tegra (provided by nvidia on their tegradeveloper website).
You have to uncompress the targetfs first :
./target_fs.sh
you should have a new directory created, namely _out/targetfs/ , with a full linux tree inside.
You need to copy the file from this new directory into your ramdisk image :
bin/udevd
bin/udevadm
lib/ld-linux.so.3
lib/libc.so.6
lib/libdl.so.2
lib/libselinux.so.1
lib/udev directory
etc/udev directory
Step 2 : Expand busybox
For conveniance, create a link to busybox for the following command in your bin directory in your ramdisk image :
ls
mkdir
mount
umount
clear
echo
sleep
mknod
ln
exec
switch_root
Step 3 : Edit init
Edit init to append the following content :

mkdir -p /var/lock

mount -t sysfs -o nodev,noexec,nosuid none /sys
mount -t proc -o nodev,noexec,nosuid none /proc
clear
sysctl -w kernel.printk="4 4 1 7" >/dev/null 2>&1
mount -t tmpfs -o mode=0755 none /dev
mknod -m 0600 /dev/console c 5 1

mknod /dev/null c 1 3
mkdir /dev/pts
mount -t devpts -o noexec,nosuid,gid=5,mode=0620 none /dev/pts

mkdir -p /dev/.udev/db/
udevd --daemon

mkdir -p /dev/.udev/queue/ /dev/.udev/rules.d/
udevadm trigger

echo -n "Waiting for devices ... "
udevadm settle
sleep 5
echo "done"

Now repack your boot image as you did in the framebuffer console.
If everything goes well, doing ls /dev should return you a whole list of device.

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