I installed Piratebox onto a Raspberry Pi2 under Arch Linux. I figured that I would share the steps I took in order to set it up. The current instructions are based on the Raspian Instructions, except tweaked for Arch.
#Setup Arch on Pi2:
Follow these instructions: http://archlinuxarm.org/platforms/armv7/broadcom/raspberry-pi-2
#Pacman - update all packages
#install lighttpd, remove autostart
#install dnsmasq, remove autostart
#install hostapd, remove autostart
#install iw
#switch bash to sh
#install wget, download piratebox
#download arch startup script
#put piratebox in correct location, setup droopy
#install startup script
#add groups
#make and install debian's Start-Stop-Daemon
#install python
#enable piratebox on startup and start
#Setup Arch on Pi2:
Follow these instructions: http://archlinuxarm.org/platforms/armv7/broadcom/raspberry-pi-2
#Pacman - update all packages
pacman -Syu
#install lighttpd, remove autostart
pacman -S lighttpd --noconfirm systemctl stop lighttpd systemctl disable lighttpd
#install dnsmasq, remove autostart
pacman -S dnsmasq --noconfirm systemctl stop dnsmasq systemctl disable dnsmasq
#install hostapd, remove autostart
pacman -S hostapd --noconfirm systemctl stop hostapd systemctl disable hostapd
#install iw
pacman -S iw --noconfirm
#switch bash to sh
rm /bin/sh ln /bin/bash /bin/sh chmod a+rw /bin/sh
#install wget, download piratebox
cd ~/ pacman -S wget --noconfirm wget http://downloads.piratebox.de/piratebox-ws_current.tar.gz tar xzf piratebox-ws_current.tar.gz
#download arch startup script
cd ~/piratebox/init.d/ wget https://raw.githubusercontent.com/PirateBox-Dev/PirateBoxScripts_Webserver/master/BuildScripts/piratebox.service
#put piratebox in correct location, setup droopy
cd ~/piratebox/ mkdir -p /opt cp -rv piratebox/ /opt cd /opt/piratebox/ sed 's#DROOPY_USE_USER="no"#DROOPY_USE_USER="yes"#' -i /opt/piratebox/conf/piratebox.conf
#install startup script
cp /opt/piratebox/init.d/piratebox.service /etc/systemd/system/piratebox.service
#add groups
groupadd nogroup; useradd -g nogroup nobody; usermod -a -G nogroup nobody;
#make and install debian's Start-Stop-Daemon
pacman -S gcc pacman -S make cd ~/ wget http://ftp.de.debian.org/debian/pool/main/d/dpkg/dpkg_1.18.3.tar.xz tar -xvf dpkg_1.18.3.tar.xz cd dpkg-1.18.3/ ./configure make cd utils/ make install start-stop-daemon
#install python
pacman -S python2 ln -s /usr/bin/python2 /usr/bin/python
#enable piratebox on startup and start
systemctl enable piratebox systemctl start piratebox