Setting the wifi on the Raspberry Pi with a TL-WN725N v2 adaptor

Since the release of the Linux kernel 3.4, the driver RTL8188eu is provided by default, which wasn’t the case some times ago: the TL-WN725N v2 wifi dongle should be working out of the box.

Install what you need

# pacman -S wpa_supplicant
Yes, that’s it… Because netctl is already installed.

Configuration of the wifi

Prepare the WPA key

# wpa_passphrase your_essid 'passphrase'

Put the passphrase between simple quotes to escape special characters.

You should get someting like:

network={
  ssid="your_essid"
  #psk="passphrase"
  psk=64cf3ced850ecef39197bb7b7b301fc39437a6aa6c6a599d0534b16af578e04a
}

Copy the psk value.

Set up netctl

To now the name of the interfaces type:
# ip link show

Here I have lo (loopback interface), eth0 (ethernet), wlan0 (wifi).

In /etc/netctl/wlan0-your_essid

Description='description'
Interface=wlan0
Connection=wireless
Security=wpa
ESSID=your_essid
IP=dhcp
Key=\"64cf3ced850ecef39197bb7b7b301fc39437a6aa6c6a599d0534b16af578e04a

Note that the value of Key is \"[what you copied before]

Test it

# netctl start wlan0-your_essid

If it works it can be enabled at boot.
# netctl enable wlan0-your_essid

If it doesn’t work, you can try to see if the problem comes from the interface or not. Using wifi-menu can be helpful. It’s a dialog in the terminal that makes things easier and in an automatic way. However it seems to have troubles with special characters in the password.

Else follow the sources …

Sources

https://wiki.archlinux.org/index.php/Wireless_network_configuration
https://wiki.archlinux.org/index.php/Netctl

Installing the Raspberry Pi

I’ve got this Raspberry Pi 1 Model B for almost 2 years. I did install ArchLinux on it a while ago and played a little. And then, because I had no project it could be used for, I just left it in a closet… Until yesterday, that a friend came out with a good idea.

Let’s start from the beginning again, and see how to install it from scratch.

Prepare the SD Card

Of course, an SD card is needed. 8 Go is really enough.

I followed the documentation of ArchLinux ARM [1], and adapted it to my needs.

In my case the SD Card was referenced in the file system as /dev/mmcblk0. Replace it by the corresponding name on your own system.

Partitioning with fdisk

We only create 3 partitions. The /boot one, the / (root) and the swap (file exchange partition). You could also separate the /home partition from the root one, but on a raspberry, it’s not so relevant[citation needed]. So we’ll have 3 partitions:

• /dev/mmcblk0p1 for /boot
• /dev/mmcblk0p2 for /
• /dev/mmcblk0p3 for the swap

With fdisk [2], nothing is actually done to the disk before you type w in the main menu to write the modification. In case you’re not sure of what you’ve done, exit the program and start again…

# fdisk /dev/mmcblk0

• Type o to clear all partitions
• Type p to list all partitions (it should be empty)

1st partition: /boot

• Type n to add a partitions, then 1 (it’s the first partition), then ENTER to begin on first sector, then +100M for the last sector
• Type t, then c to set the first partition to type W95 FAT32

2nd partition: /

• Type n to add a partitions, then ENTER (it’s the second partition), then ENTER to begin on next sector, then +XXXM for the last sector with XXX = total_size-1G
• Type t, then 83 to set the first partition to type Linux

3rd partition: swap

• Type n to add a partitions, then ENTER (it’s the third partition), then ENTER to begin on next sector, then ENTER for the last sector
• Type t, then 82 to set the first partition to type Linux Swap

The partition table can no be written and exited with w

Creation of the filesystems

# mkfs.vfat /dev/mmcblk0p1
# mkfs.ext4 /dev/mmcblk0p2

Populationg the filesytems

First mount the partitions:
$ mkdir {boot,root}
# mount /dev/mmcblk0p1 boot
# mount /dev/mmcblk0p2 root

Download and extract the root filesystem:
$ wget http://archlinuxarm.org/os/ArchLinuxARM-rpi-latest.tar.gz
# bsdtar -xpf ArchLinuxARM-rpi-latest.tar.gz -C root
# sync

Move boot files to the first partition:
# mv root/boot/* boot

Unmounting the partitions and starting the Raspberry

Unmount the two partitions:
# umount boot root

The SD card can now be inserted into the Raspberry Pi. When the Raspberry Pi came out, you first add to connect to a screen and keyboard to go through the installation, configure the connection and ssh. But hopefully, you can now directly connect with the ethernet, and apply the 5V power. Then use the SSH to the IP address given to the board by your router/DHCP. Login as the default user alarm with the password alarm. The default root password is root.

ssh alarm@alarmpi

Setup the swap

Check that the swap is off (the next command shouldn’t output anything):
# swapon -s

Setup the swap partition (remember: ours is the 3rd one) and turn it on:
# mkswap /dev/mmcblk0p3
# swapon /dev/mmcblk0p3

Systemd will by default start it at boot.

Setup the environment

Accounts

Change the root password:
# passwd

Add your user account:
# useradd -c MyName -md /home/mylogin mylogin
# passwd mylogin

Install the basic packages

# pacman -S --needed base-devel
# pacman -S vim zsh python ...

You now have a simple ArchLinux on your Raspberry Pi, that you can use like any other Linux system…

Sources

[1] http://archlinuxarm.org/platforms/armv6/raspberry-pi
[2] http://tldp.org/HOWTO/Partition/fdisk_partitioning.html
[3] https://wiki.archlinux.org/index.php/Swap