Bootstrap sdcard with ArchLinuxARM for RaspberryPi 2/3

alarm-rpi.sh

#!/bin/bash
DISK=$1
if [[ -z $DISK ]]; then
  echo "Please supply the target disk i.e. /dev/sdb"
  exit 1
fi

ALARM_VERSION=$2
if [[ -z $ALARM_VERSION ]]; then
  ALARM_VERSION=3
fi
echo "Installing 'ArchLinuxARM-rpi-$ALARM_VERSION' on '$DISK'"

#Zero the beginning of the SD card or eMMC module
dd if=/dev/zero of=$DISK bs=1M count=8

# to create the partitions programatically (rather than manually)
# we're going to simulate the manual input to fdisk
# The sed script strips off all the comments so that we can
# document what we're doing in-line with the actual commands
# Note that a blank line (commented as "defualt" will send a empty
# line terminated with a newline to take the fdisk default.
# Start fdisk to partition the SD card
# At the fdisk prompt, create the new partitions
sed -e 's/\s*\([\+a-z0-9A-Z]*\).*/\1/' << EOF | fdisk $DISK
  o # clear the in memory partition table
  n # new partition
  p # default p # primary partition
  1 # default 1 # partition number 1
  2048 # default - start at beginning of disk
  +100M #
  t # type W95 FAT32 (LBA).
  c
  n # new ext4
  p
  2 # default 2
    # default start
    # default end
  w # write the partition table
EOF

sleep 1

# Create and mount the FAT filesystem
mkfs.vfat ${DISK}1
sleep 1

# Create the ext4 filesystem
yes | mkfs.ext4 ${DISK}2
sleep 1

# Create dirs
mkdir root boot

# Mount the FAT filesystem
mount ${DISK}1 boot

# Mount the filesystem
mount ${DISK}2 root

# Download and extract the root filesystem (as root, not via sudo)
curl -LO http://os.archlinuxarm.org/os/ArchLinuxARM-rpi-${ALARM_VERSION}-latest.tar.gz
sleep 1
bsdtar -xpf ArchLinuxARM-rpi-${ALARM_VERSION}-latest.tar.gz -C root
sync

# Flash the bootloader files
mv root/boot/* boot

# Unmount the partition
umount boot root

# Clean-up
rm -rf root/ boot/ ArchLinuxARM-rpi-*.tar.gz