Install Arch Linux ARM for Raspberry Pi 3 on SD Card (with commands to configure WiFi before first boot).

install-arch-linux-rpi-zero-w.sh

#!/bin/bash -x
dev=$1
cd $(mktemp -d)
if (mount | grep ${dev}); then 
umount ${dev}1
umount ${dev}2
fi

archlinux=/tmp/ArchLinuxARM-rpi-2-latest.tar.gz
url=http://os.archlinuxarm.org/os/ArchLinuxARM-rpi-2-latest.tar.gz

curl -L -o $archlinux -z $archlinux $url
parted -s $dev mklabel msdos
parted -s $dev mkpart primary fat32 1 128
parted -s $dev mkpart primary ext4 128 -- -1
sleep 2
mkfs.vfat ${dev}1
mkfs.ext4 -F ${dev}2
mkdir -p root
mount ${dev}2 root
mkdir -p root/boot
mount ${dev}1 root/boot

tar -xpf $archlinux -C root
sync

mount -o bind /proc root/proc
mount -o bind /dev root/dev

ln -s /usr/lib/systemd/system/wpa_supplicant@.service root/etc/systemd/system/multi-user.target.wants/wpa_supplicant@wlan0.service
cp /usr/bin/qemu-arm-static root/usr/bin/

cat <<EOT >> root/etc/modules-load.d/raspberrypi.conf
i2c-dev
i2c-bcm2708
EOT

cat <<EOT >> root/etc/systemd/network/25-wireless.network
[Match]
Name=wlan0

[Network]
DHCP=ipv4
EOT

cat <<EOT >> root/etc/systemd/network/25-wireless.network
[Match]
Name=wlan0

[Network]
DHCP=ipv4
EOT

mkdir -p root/run/systemd/resolve/
echo "nameserver 8.8.8.8" > root/run/systemd/resolve/resolv.conf

cat <<EOT >> root/root/setup_chroot.sh
#!/bin/bash
pacman -Syu --noconfirm
pacman -S wpa_supplicant --noconfirm
rm /run/systemd/resolve/resolv.conf
EOT

chmod a+x root/root/setup_chroot.sh
chroot root /root/setup_chroot.sh

cat <<EOT >> root/etc/wpa_supplicant/wpa_supplicant-wlan0.conf
network={
ssid="wifissid"
psk="wifikey"
key_mgmt=WPA-PSK
}
EOT

echo "dtparam=i2c=on" >> root/boot/config.txt

umount root/proc
umount root/dev