Pi 🫐

Introduction

I have an old (version 3) Raspberry Pi from the era in which I worked on IoT. Here I tried to configure it with ArchLinux (aarch64 architecture). Also I bought a new Raspberry Pi (version 4) and I want to install ArchLinux on it (aarch64 as well).

Information

BCM2835

The BCM2835 is the Broadcom chip used in the Raspberry Pi Model A, B, B+, the Compute Module, and the Raspberry Pi Zero. Datasheet

BCM2836

The Broadcom chip used in the Raspberry Pi 2 Model B. The underlying architecture in BCM2836 is identical to BCM2835. The only significant difference is the removal of the ARM1176JZF-S processor and replacement with a quad-core Cortex-A7 cluster.

BCM2837

This is the Broadcom chip used in the Raspberry Pi 3, and in later models of the Raspberry Pi 2. The underlying architecture of the BCM2837 is identical to the BCM2836. The only significant difference is the replacement of the ARMv7 quad core cluster with a quad-core ARM Cortex A53 (ARMv8) cluster. The ARM cores run at 1.2GHz, making the device about 50% faster than the Raspberry Pi 2. The VideoCore IV runs at 400MHz.

BCM2837B0

This is the Broadcom chip used in the Raspberry Pi 3B+ and 3A+. The underlying architecture of the BCM2837B0 is identical to the BCM2837 chip used in other versions of the Pi. The ARM core hardware is the same, only the frequency is rated higher. The ARM cores are capable of running at up to 1.4GHz, making the 3B+/3A+ about 17% faster than the original Raspberry Pi 3. The VideoCore IV runs at 400MHz. The ARM core is 64-bit, while the VideoCore IV is 32-bit. The BCM2837B0 chip is packaged slightly differently to the BCM2837, and most notably includes a heat spreader for better thermals. This allows higher clock frequencies, and more accurate monitoring and control of the chip’s temperature.

BCM2711

This is the Broadcom chip used in the Raspberry Pi 4 Model B. The architecture of the BCM2711 is a considerable upgrade on that used by the SoCs in earlier Raspberry Pi models. It continues the quad-core CPU design of the BCM2837, but uses the more powerful ARM A72 core. It has a greatly improved GPU feature set with much faster input/output, due to the incorporation of a PCIe link that connects the USB 2 and USB 3 ports, and a natively attached Ethernet controller. It is also capable of addressing more memory than the SoCs used before.

The ARM cores are capable of running at up to 1.5 GHz, making the Pi 4 about 50% faster than the Raspberry Pi 3B+. The new VideoCore VI 3D unit now runs at up to 500 MHz. The ARM cores are 64-bit, and while the VideoCore is 32-bit, there is a new Memory Management Unit, which means it can access more memory than previous versions.

The BCM2711 chip continues to use the heat spreading technology started with the BCM2837B0, which provides better thermal management.

• Processor: Quad-core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5 GHz.
• Memory: Accesses up to 8GB LPDDR4-2400 SDRAM (depending on model)
• Caches: 32 KB data + 48 KB instruction L1 cache per core. 1MB L2 cache.
• Multimedia: H.265 (4Kp60 decode); H.264 (1080p60 decode, 1080p30 encode); OpenGL ES, 3.0 graphics
• I/O: PCIe bus, onboard Ethernet port, 2 × DSI ports (only one exposed on Raspberry Pi 4B), 2 × CSI ports (only one exposed on Raspberry Pi 4B), up to 6 × I2C, up to 6 × UART (muxed with I2C), up to 6 × SPI (only five exposed on Raspberry Pi 4B), dual HDMI video output, composite video output.

config.txt

The Raspberry Pi uses a configuration file instead of the BIOS you would expect to find on a conventional PC. The system configuration parameters, which would traditionally be edited and stored using a BIOS, are stored instead in an optional text file named config.txt.

read more

in Go

Raspberry Pi GPIO library for golang

Pioneer 600

Raspberry Pi Expansion Board, Miscellaneous Components, All-in-One read more

• CP2102: USB To UART Bridge
• DS3231: Extremely Accurate I2C-IntegratedRTC/TCXO/Crystal
• BMP180: Digital pressure sensor
• SSD1306: OEL Display Module
• PCF8591: 8-bit A/D and D/A converter
• PCF8574: Remote 8-bit I/O expander for I2C-bus

A note on stability 📝

Arch Linux ARM on a Pi 4 is a great learning / tinkering platform, but it is not what I would pick for a device that needs to "just work" unattended:

• Rolling release + a smaller ARM testing base means breakage after a large pacman -Syu is more common than on x86_64 Arch. Keyring drift (archlinux-keyring / archlinuxarm-keyring) can block pacman until fixed by hand — painful on a headless board.
• There is no Pi-specific tuning out of the box (log2ram, zram, SD-friendly I/O defaults). You assemble it yourself.
• HAT overlays, libcamera, and hardware video decode are documented almost exclusively against Raspberry Pi OS; Arch users are on their own.
• Stick to the linux-rpi kernel (not linux-aarch64) — it's the one actually maintained for Pi hardware.

If long-term stability is the priority, prefer one of:

1. Raspberry Pi OS (64-bit, Trixie) — official, firmware-matched, boring in the good way.
2. Ubuntu Server 24.04 LTS for Pi — 5-year Canonical support.
3. Debian ARM64 — upstream Debian without the Pi skin.
4. openSUSE MicroOS / Fedora IoT — transactional updates for appliance-style deployments.

The rest of this document focuses on Arch because that's the hobby track I'm on, but a Raspberry Pi OS quickstart is included below.

Raspberry Pi OS quickstart 🥧

The officially supported path. Works on Pi 3, 4, 5, and Zero 2 W.

1. Download Raspberry Pi Imager from https://www.raspberrypi.com/software/ (the Imager is the recommended tool; do not hand-flash legacy .img files unless you know why).

2. Launch the Imager, pick:

   • Device: Raspberry Pi 4
   • OS: "Raspberry Pi OS (64-bit)" — based on Debian Trixie as of 2026
   • Storage: your SD card

3. Click the gear / "Edit settings" (or press Ctrl+Shift+X) to pre-configure the image before flashing:

   • Set hostname (e.g. pi.parham.home)
   • Create the initial user + password (the default pi/raspberry account was removed in Bookworm; you must supply your own)
   • Enable SSH and paste your public key
   • Configure Wi-Fi SSID / password and locale
   • This populates a firstrun.sh that executes on first boot.

4. Flash, insert the SD card, connect Ethernet (if available), and power on.

5. From your workstation:

   ssh parham@pi.parham.home
   sudo apt update && sudo apt full-upgrade
   sudo rpi-update        # only if you actually need bleeding-edge firmware

6. Useful first-run commands:

   sudo raspi-config      # interactive: enable I2C / SPI / camera / serial
   sudo apt install git vim tmux

Note: Raspberry Pi does not support in-place upgrades between major releases (e.g. Bookworm → Trixie). The supported path is to flash a fresh image and reinstall your applications.

Arch on ARM 💪

1. Start fdisk to partition the SD card

2. At the fdisk prompt, delete old partitions and create new ones:

   1. Type o. This will clear out any partitions on the drive.
   2. Type p to list partitions. There should be no partitions left.
   3. Type n, then p for primary, 1 for the first partition on the drive, press ENTER to accept the default first sector, then type +200M for the last sector.
   4. Type t, then c to set the first partition to type W95 FAT32 (LBA).
   5. Type n, then p for primary, 2 for the second partition on the drive, and then press ENTER twice to accept the default first and last sector.
   6. Write the partition table and exit by typing w.

3. sudo pacman -Syu dosfstools to use FAT filesystem.

4. Create and mount the ext4 filesystem:

   mkfs.ext4 /dev/sdX2
   mount /dev/sdX2 /mnt

5. create and mount the FAT filesystem:

   mkfs.vfat /dev/sdX1
   mkdir /mnt/boot
   mount /dev/sdX1 /mnt/boot

6. Download (https://archlinuxarm.org) and extract the root file system (as root, not via sudo):

   # aarch64 (rpi3)
   aria2c http://os.archlinuxarm.org/os/ArchLinuxARM-rpi-aarch64-latest.tar.gz
   tar xvfz ArchLinuxARM-rpi-aarch64-latest.tar.gz -C /mnt

   # aarch64 (rpi4) — the rpi-aarch64 tarball supports both Pi 3 and Pi 4
   aria2c http://os.archlinuxarm.org/os/ArchLinuxARM-rpi-aarch64-latest.tar.gz
   tar xvfz ArchLinuxARM-rpi-aarch64-latest.tar.gz -C /mnt

7. Insert the SD card into the Raspberry Pi, connect Ethernet cable, and apply 5V power.

8. With models that has built-in Bluetooth support you need to apply following layout and kernel parameters to make the serial console work.

   config.txt:

   dtoverlay=miniuart-bt
   

   cmdline.txt:

   console=tty1 console=ttyAMA0,115200
   

Initiation

1. Use the serial console or SSH to the IP address given to the board by your router.

   1. Login as the default user alarm with the password alarm.
   2. The default root password is root.
   3. Change both passwords immediately with passwd (as alarm) and passwd (as root) before exposing the device to any network.

2. Initialize the pacman keyring and populate the Arch Linux ARM package signing keys:

   su
   pacman-key --init
   pacman-key --populate archlinuxarm
   
   pacman -Syu
   pacman -S --needed base-devel

Create Me 🐼

su

useradd -m parham
# `wheel` is the conventional admin group on Arch; it already exists.
usermod -a -G wheel parham
passwd parham

# uncomment the `%wheel ALL=(ALL:ALL) ALL` line
EDITOR=vim visudo

Network 🛜

we use systemd-networkd for networking:

[Match]
Name=eth0

[Network]
Address=192.168.73.98/24
Gateway=192.168.73.254
DNS=192.168.73.254
DNS=8.8.8.8

Save the above configuration in /etc/systemd/network/20-wired.network. Then enable it with the following command:

sudo systemctl restart systemd-networkd

For Wi-Fi, netctl / wifi-menu has been removed from Arch Linux ARM — use iwd instead, either standalone or as a backend for systemd-networkd / NetworkManager.

sudo pacman -S iwd
sudo systemctl enable --now iwd.service

# interactive client
iwctl
# at the prompt:
#   device list
#   station wlan0 scan
#   station wlan0 get-networks
#   station wlan0 connect "Parham-Main"

To combine iwd with the existing systemd-networkd setup, add a matching .network file for wlan0 under /etc/systemd/network/ and let iwd handle authentication.

Ready for Ansible 🚀

First copy the ssh public key into the host and then install the following packages, after that you are ready for Ansible.

ssh-copy-id

sudo pacman -Syu python inetutils

How to use AUR

In order to use AUR on ARM Arch, we can clone it and make it manually. For example:

git clone https://aur.archlinux.org/blocky.git
cd blocky
makepkg -si

GPIO (libgpiod)

The legacy /sys/class/gpio sysfs interface has been removed from modern Linux kernels. The current best practice is libgpiod with the gpioset / gpioget CLI tools.

sudo pacman -S libgpiod

# drive GPIO26 high, works across Pi 3/4/5 via the named line
gpioset GPIO26=1

# hold the line high for 2 seconds, then release
gpioset --hold-period 2s -t0 GPIO26=1

The led.sh helper in this repo wraps gpioset with positional arguments.

modules-load.d

modules-load.d/raspberrypi.conf lists kernel modules to autoload at boot (I²C, SPI, etc.). Copy it to /etc/modules-load.d/ on the target device.

LoRa Modules

• SX1268 433M LoRa HAT
• SX1302 868M LoRaWAN Gateway