Raspberry Pi Zero 2 W

· 412 words · 2 minute read

Bootstrap Raspberry Pi Zero 2 W with Ubuntu using cloud-init. OTG configured as network card, WiFi, ssh-keys from GitHub and zram swap enabled. All examples are made to be run on a Fedora Desktop. Adjust scripts if you use another distro.

This blog post is written in the influence of a cold. Take care with your copy and pasting. Hope you enjoy this nifty way to bootstrap Ubuntu PI systems.

👍 Tip! Fetch your public SSH keys from GitHub with

wget -O - https://github.com/username.keys

Before you begin 🔗

If you want to access your Pi over OTG, use connection sharing, for example in NetworkManger. Remember to open incoming ports for DHCP and DNS in your firewall.

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Write OS to SD card 🔗

Download Raspberry Ubuntu from Install Ubuntu on a Raspberry Pi. Why Ubuntu and not Raspberry Pi OS. Ubuntu contain btrfs kernel module in initramfs.

😯 Important! Do not copy and paste from the internet without examine the code. Ensure that your SD card is mounted on /dev/sdb or change all the scripts to your device.

sudo bash <<EOF
  xzcat ubuntu-22.04-preinstalled-server-arm64+raspi.img.xz | dd of=/dev/sdb bs=1M status=progress
EOF

Take out and put the SD card back into to the computer. Let the computer mount the file systems before you continue.

cloud-init 🔗

Export your WiFi network and password to shell variables.

export WIFI_NAME="internett"
export WIFI_PASS="password"

Write cloud-init configuration files.

sudo bash <<EOF
  cd /run/media/${USER}
  cat <<CONF > system-boot/user-data
#cloud-config
hostname: zero
password: ubuntu
ssh_pwauth: true
ssh_import_id:
  - gh:${USER}

write_files:
  - path: /boot/firmware/config.txt
    append: true
    content: |
      dtoverlay=dwc2
  - path: /etc/modules
    permissions: '0644'
    content: |
      dwc2
      g_ether
  - path: /etc/modprobe.d/g_ether.conf
    permissions: '0644'
    content: |
      options g_ether host_addr=42:00:00:00:00:02 dev_addr=42:00:00:00:00:01

packages:
  - linux-modules-extra-raspi
  - zram-tools
package_update: true

timezone: UTC

runcmd:
  - /usr/sbin/update-initramfs -u
  - /usr/bin/systemctl enable zramswap --now

power_state:
  delay: now
  mode: reboot
  message: reboot into new initramfs
  condition: true
CONF

  cat <<CONF > writable/etc/cloud/cloud.cfg.d/10-network.cfg
network:
  version: 2
  ethernets:
    usb0:
      dhcp4: true
      dhcp6: true
      optional: true
  wifis:
    wlan0:
      dhcp4: yes
      dhcp6: yes
      optional: true
      access-points:
        "${WIFI_NAME}":
            password: "${WIFI_PASS}"
CONF
EOF

Convert root file system to Btrfs 🔗

If you want to use Btrfs instead of default ext4.

sudo bash <<EOF
  cd /run/media/${USER}
  sed -i 's/ext4/btrfs/' system-boot/cmdline.txt
  sed -E -i 's|(.*)ext4.*|\1btrfs compress=zstd:1,noatime,nodiratime 0 0|' writable/etc/fstab
  umount system-boot writable
  btrfs-convert -p /dev/sdb2
EOF

Re-mount SD card and then run the script to clean up after conversion and compress existing operative system.

sudo bash <<EOF
  cd /run/media/${USER}
  btrfs sub del writable/ext2_saved
  btrfs fi def -czstd -r -v writable/
EOF
network pi