Stage 3 of 6 · Lab, on the lab PC · about 30 minutes
Write the image
Raspberry Pi Imager copies a complete operating system onto your boot drive, a microSD card or a USB SSD, and stamps your identity on it: a hostname, an account, a keyboard, a time zone, a Wi-Fi network and SSH. The one decision that cannot be undone is which drive it writes to.
What an image is, and what Imager does with it
A Raspberry Pi OS image is a byte-for-byte picture of a whole disk: a partition table, a small FAT boot partition with the firmware and kernel, and a large ext4 root partition with Linux and its files. Imager downloads that image (or takes one you already have), writes it sector by sector onto the drive you select, reads it back to verify it, and applies your customisation so the Pi is ready at first boot.
Imager does
- List the OS versions that fit your model
- Erase and repartition the selected drive
- Write the image and verify it
- Pre-set hostname, user, locale, Wi-Fi, SSH
Imager does not
- Install software inside the OS (that is
apt, later) - Update an existing installation (it replaces it)
- Recover a drive after you accept the erase warning
- Configure enterprise Wi-Fi that needs a username
Get Raspberry Pi Imager
The lab PCs should already have it. If not, or at home, install the current version (2.x, checked August 2026) from the official page.
Windows and macOS
Download the installer from raspberrypi.com/software, run it, and open Raspberry Pi Imager from the Start menu or Applications.
Ubuntu / Debian Linux
$ sudo apt update
$ sudo apt install rpi-imager
$ rpi-imagerIf apt update fails with certificate or date errors, the PC clock is wrong, usually because the campus network blocks public time servers. Michel Paquette's clock fix points the system clock at the campus time server instead; apply it, then repeat.
The Imager flow
Step by step
The screenshots below are from the official Raspberry Pi documentation (CC BY-SA 4.0) and show a card reader on macOS. Your screen will look the same: a microSD card sits in a card reader exactly as shown, and a USB SSD simply appears as an external drive.
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Confirm your boot drive may be erased
Read the label on the drive the teacher lent you, microSD card or SSD, and compare it with the station list. A microSD card goes into the station's card reader; an SSD plugs in by USB. Unplug every other USB stick or external drive from the lab PC so yours is the only removable drive. If the drive contains anything from a previous student, it is about to disappear; that is expected.
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Open Imager and select your device
Select Raspberry Pi 5 or Raspberry Pi 4. The Raspberry Pi 400 belongs to the Pi 4 family. Then press Next. -
Select the operating system
Choose Raspberry Pi OS (64-bit), the version with desktop marked Recommended. Not Lite (no desktop), not Full (extra software you do not need). If the teacher hands out a cached image file, scroll to Use custom and pick that file instead; it saves the room from downloading the same gigabyte at once. -
Select the storage: your drive, nothing else
Match the entry to your drive by model name and capacity (a microSD card usually shows as a generic card reader with the card's size). Leave Exclude system drives ticked. Trick: open this screen before inserting the drive, insert it, and select the entry that appears. Stop
If two entries look alike, do not guess. Cancel, unplug everything except your drive, and come back. Selecting the lab PC's disk or a classmate's drive destroys it.
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Customisation, part 1: hostname and user
Hostname: your last name followed by -pi, in lowercase, letters, digits and hyphens only, e.g.lastname-pibecomestremblay-pifor a student named Tremblay. It must be unique in the room. Username: your first name in lowercase. Password: one you will remember; there is no reset by e-mail. -
Customisation, part 2: locale and keyboard
Time zone America/Toronto (Montréal uses the same zone). Keyboard layout: the layout of the physical Pi keyboard at your station, which is us in D-221. A wrong layout makes symbols such as
@,|and~land on the wrong keys, and passwords then fail silently. -
Customisation, part 3: Wi-Fi
Enter the class network name and password written on the board, with country CA. The College's enterprise Wi-Fi (the one with a username) cannot be set up here; Imager only knows password-protected networks. If the class network is wired, skip Wi-Fi and use the Ethernet cable. -
Customisation, part 4: enable SSH
Turn Enable SSH on and keep password authentication for today. In Week 3 you will switch to key-based authentication, which is stronger. Leave Raspberry Pi Connect off. -
Review, then accept the erase warning on purpose
Read the summary: device, OS, storage and the list of customisations. If anything is wrong, press Back now. 
Before pressing I understand, erase and write, say the SSD label and capacity out loud to your partner. It sounds silly and it prevents the worst mistake of the day. -
Wait for writing and verification
Writing takes a few minutes; verification reads every byte back and takes about as long again. Do not remove the drive, close Imager, or put the PC to sleep. A failed verification means a bad drive, cable, enclosure or card reader, not a message to click past; write once more and, if it fails again, ask for another drive.
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Eject the drive
When Imager reports success, eject the drive with the operating system's safe-remove function (Imager can do it for you), then remove it. It is now a bootable Raspberry Pi drive that knows your name.
Your settings, on one line
Write these down before you leave the lab PC. You will type them again on the Pi and in ssh.
| Setting | Value to use in D-221 | Why |
|---|---|---|
| Device | Raspberry Pi 5, or Raspberry Pi 4 (also for the Pi 400) | Filters the OS list and settings for your board |
| Operating system | Raspberry Pi OS (64-bit) with desktop (Debian 13 "Trixie" based, June 2026 release) | Desktop for today, 64-bit for current packages |
| Storage | The teacher-lent boot drive (microSD or SSD), identified by model and capacity | The only irreversible step |
| Hostname | lastname-pi | Unique name; you reach the Pi as lastname-pi.local |
| Username / password | First name in lowercase / your choice | Your Linux account; needed for sudo and ssh |
| Time zone | America/Toronto | Correct clock, correct log timestamps |
| Keyboard | us | Matches the lab keyboard |
| Wi-Fi | Class network from the board, country CA | Enterprise Wi-Fi cannot be configured in Imager |
| SSH | Enabled, password authentication | Remote terminal from the lab PC; keys come in Week 3 |
Old instructions to ignore
Older tutorials and videos still rank well in search results. If you see any of these, you are reading something out of date:
- NOOBS. A menu-based installer from before 2020. Replaced by Imager.
- A default
piuser with passwordraspberry. Removed. You create the account in Imager; a Pi with no account cannot be logged into. - Dropping
wpa_supplicant.confinto the boot partition to set up Wi-Fi. Ignored since Raspberry Pi OS Bookworm. Use Imager or the desktop. - An empty
sshfile in the boot partition. Still works, but the SSH toggle in Imager is the intended way. - Imager 1.x screenshots with three big buttons and settings hidden behind Ctrl+Shift+X. The 2.x flow starts with the device.
- Full-size HDMI cables. Pi 4, 400 and 5 use micro-HDMI.
- "You must use a microSD card" or "you must use an SSD." The Pi 4, 400 and 5 boot from either. What matters is writing to the right drive and, with an SSD, keeping the card slot empty.
Before you remove the drive
Check yourself
Which single Imager choice can destroy someone's data?
Why does the room need unique hostnames?
hostname.local. Two Pis with the same name answer to the same address and you cannot tell which one you are logged into.