Configuring a Raspberry Pi from fresh install¶

I recently bought a new SD card for my years-old pi, and wanted to reformat and configure the thing properly. I first attempted to copy the existing OS onto the disk, and then expand the partition but apparently NOOBS prevents this from being a straight forward task. Even attempts using fdisk just seemed to fragment the partitions, so instead I just created a fresh install. Here are my notes for how I achieved this.

Table of Contents¶

Formatting an SD card for Raspbian
1. OSX: using diskutil
Backing up disk images
Some quality of life tips

Formatting an SD card for Raspbian¶

If the SD card is >32 GB, it can be necessary to use a special formatting tool; the pi can only use FAT8, FAT16 or FAT32 file formats (OSX: that’s MS-DOS, not ExDOS). Since I mainly work on OSX, the following guide will follow the steps for my OS (I may write up guides for other OSs later).

OSX: using `diskutil`¶

After plugging in the desired SD card to use in the Raspberry Pi, we need to identify the device associated

diskutil list

If the SD is recognized, you’ll probably see something like

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
    FDisk_partition_scheme                        *15.9 GB    disk2
            Windows_FAT_16 RECOVERY                1.7 GB     disk2s1
                     Linux                         33.6 MB    disk2s5
            Windows_FAT_32 boot                    69.2 MB    disk2s6
                     Linux                         14.1 GB    disk2s7

for an external disk. If this is a pre-existing OS you want to backup, see the section on backing up disk images. From this output we can identify the correct device as /dev/disk2; we’ll unmount it so we can start tampering with the configuration

diskutil unmountDisk /dev/disk2

The first thing we’ll want to do is erase the SD card and reformat it with FAT32; we can achieve this all in one step with

diskutil eraseDisk MS-DOS [NAME] /dev/disk2

This will create essentially a single volume on the SD card, spanning the full storage. Next, we’ll grab our operating system image from either the official repository, or some other source. We then flash the .img onto the SD card using dd; we set a few parameters to ensure the block size is 1M and that the input is padded to the buffer size using sync; for my case, the command looked like this

sudo dd bs=1m if=2020-02-13-raspbian-buster-lite.img of=/dev/rdisk2 conv=sync

Note that the identifier is preceded with an r in /dev/rdisk2; this is the raw partition, allowing us to write one byte at a time (the other being the block device for regular IO).

Unfortunately, dd doesn’t provide a status bar or indication text, but recent versions of GNU do include a status=progress verb to be used at the end of the command. I don’t believe OSX supports this function however, so personally I track the progress using a detail I found in the man page

If dd receives a SIGINFO (see the status argument for stty(1)) signal, the current input and output block counts will be written to the standard error output in the same format as the standard com- pletion message. If dd receives a SIGINT signal, the current input and output block counts will be written to the standard error output in the same format as the standard completion message and dd will exit.

So, on OSX we can output the status by pinging

sudo kill -INFO pid

where pid is the process ID of dd.

Once this copy has completed, the SD card is ready to be used with the Pi.

Backing up disk images¶

If you want to create a disk image from a given SD card, once you have identified the associated device, doing so is trivial

sudo dd if=/dev/diskID of=DISK_IMAGE_NAME.img

Some quality of life tips¶

I like to have my Pi’s feel different from other machines, so I tend to tweak the same settings over and over; here are my notes for how I do that.

Getting Docker¶

Docker is installed with a one-liner:

curl -fsSL https://get.docker.com -o get-docker.sh && sudo sh get-docker.sh

Add a non-root user to the docker group, e.g. the default pi user

sudo usermod -aG docker pi

and you’re away! Test it all with

docker run hello-world

#### docker-compose Docker composed is easiest to install through the Python package manager

sudo apt-get install python3-pip
sudo pip3 install docker-compose

Enabling WiFi before boot¶

You can configure the pi to connect to a wifi router before you boot the device; mount the SD card, and in the boot volume, create a new file with the contents:

country=gb
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
ssid="SSID"
scan_ssid=1
psk="WIFI_PASSWORD"
}

The country codes follow Alpha-2 ISO 3166 format.

That’s it; use arp -a or nmap -sn to scan for the pi once it connects!

Enabling WiFi after boot¶

This is as simple as using the interactive sudo raspi-config, and navigating to the Network Options.

SSH enable in headless mode¶

Simply navigate to the boot directory, and create an empty ssh file; e.g.:

touch Volumes/boot/ssh

and then (re)boot the device.

Changing the hostname¶

The hostname is located in a few different locations, so we want to edit the files

/etc/hostname
/etc/hosts

and change, presumably, raspberrypi to whatever you’d like the hostname to be, and then reboot. Note, you may also need to run hostname upon reboot, but I have only read this, and did not personally need to.

Disabling unneeded hardware¶

In /boot/config.txt you can set a variety of different parameters that control how the raspi boots up. For example, to disable WiFi and Bluetooth completely, add the line:

dtoverlay=disable-wifi
dtoverlay=disable-bt

These are use-case specific, and more can be seen here.

notes

Configuring a Raspberry Pi from fresh install

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