How to Add an SSD To Your Raspberry Pi 5 with the M.2 HAT

SSDs on the Raspberry Pi are not new. For many years now people have been enjoying NVME speeds on Raspberry Pis through the use of NVMe-to-USB adapters. But long gone are the days of annoying adapters flopping around and occupying a precious USB port with the release of the Raspberry Pi 5. The Pi 5 brought a long-awaited PCIE slot, opening up the possibilities of connecting M.2 devices directly to the board through the use of the official Raspberry Pi 5 M.2 HAT (Hardware Attached on Top).

This M.2 PCIE HAT can be used for many things (even connecting a GPU to it), but the most common application will be booting the Pi 5 off an NVME SSD. As we will see in this guide, booting the Pi 5 with an NVME HAT provides us with an astounding boost in read and write speeds, as well as providing a nice and compact form factor for it all. 

In this guide, we will be covering:

• What You Will Need
• Connecting the HAT and SSD
• Installing Pi OS From Scratch
• Alternative: Cloning an Existing OS
• Selecting Boot Order
• Optional: Enabling Gen 3 PCIE
• Benchmarks

The M.2 HAT is incredibly easy to install, but can be a little finnicky. We found the easiest method was to first install the standoffs onto the Pi 5.

Then connect the ribbon cable by first lifting the Pi 5's connector head.

Then inserting the ribbon cabble and pushing the head back down to lock it in place.

Ribbon cables like these can be fragile, so avoid tearing it and bending it too much.

Then screw the HAT to the standoffs.

Insert the NVME into the top of the HAT, ensuring that you come in at about a 30 degree angle like in the picture.

And finally fastening the NVME down with the small silver hold screw.

All finished!

If you happen to have an NVME to USB adapter lying around, this step is incredibly easy. You can just plug your SSD into your computer and install it with the Pi OS Imager like you would a micro SD card.

For those of us who don't have one, we will have to follow another process, it's not difficult, it just has more steps. We will need to install Pi OS onto a micro SD card. Then we will boot into Pi OS on the Pi 5 (on the micro SD), and then use the Pi OS imager (on the Pi 5) to install the OS onto the NVME drive.

To start, ensure that you have the Raspberry Pi Imager installed, and the micro SD card plugged into your computer. Then in the imager, we will select the Pi 5 as the device, Raspberry Pi OS (64-bit) as our operating system, and the plugged-in micro SD card as our storage device. 

NOTE: INSTALLING PI OS ONTO THE MICROSD CARD WILL WIPE ALL DATA ON IT.

Once the installation is finished, insert the SD card into your Pi 5, and power on your Pi 5 with a keyboard, mouse and monitor. You will be greeted by a first-time setup and you can breeze through this as we will not be using this installation of Pi OS on the SD card. Just ensure that the Pi is connected to the internet.

Once you are in a desktop environment head on over to the Raspberry Pi Imager, it comes pre-installed with Pi OS. You can check if your NVME drive is correctly installed as you should be able to should see it listed under storage devices.

If your device is not being correctly recognised, double-check the ribbon cable connection (replug it in), and check that your system is up to date. This can be done in the terminal with:

sudo apt-get update

sudo apt-get upgrade

Now we just repeat the same process to install the Pi OS onto the NVME drive. Select Pi 5 as the Device, Raspberry Pi OS (64-bit) as the operating system and the SSD as the storage.

After it has finished installing, our NVME is now ready to go. But we have one more helpful step left and that is changing the boot order.

If you have an existing image of Pi OS that you want to keep using (it must be Bookworm or newer), we also have the option to clone an existing installation over to the NVME instead of performing a clean install. 

The process is also incredibly easy and can be done through the SD Card Copier that comes pre-installed with Pi OS. Just ensure you select to copy from your existing installation to the NVME SSD.

The NVME is now able to be booted from, but it isn't first in the boot order. The Pi will try to boot from the Micro SD card first, then the NVME drive. If you don't have a bootable micro SD card plugged in then this won't be an issue, but it is simple to change this boot order setting.

To change the boot order open the raspi-config tool, this can be done in a terminal window by punching in:

sudo raspi-config

Then use the arrow keys to navigate to Advanced Options > Boot Order and then select NVME/USB Boot. The terminal will throw a few lines of code as it makes this change to the Pi's firmware.

You may run into this EEPROM error while trying to set the boot order. This can be fixed in the same menu by navigating to Advanced Options > Bootloader Version and selecting "E1 Latest". This will update the Pi 5's bootloader to the newest version and after restarting, you should now be able to set the boot order.

After rebooting, you should be now in Pi OS on the NVME, and if you have just freshly installed it you will be greeted with the first-time setup. 

If you are ever unsure which drive you are booted off, you can always check by opening the terminal and typing in:

df /boot -h

If it starts with "mmcblk", you are booting off an SD card, and an NVME will start with "nvme".

Congratulations, you have now fully set up your NVME SSD with the Pi HAT!

By default, the Pi 5 has its PCIE set to Gen 2 speeds, but it is possible to set it to Gen 3 speeds, theoretically doubling the maximum read and write speeds of our NVME.

There is a word of warning here. Although it is possible to enable Gen 3 speeds, it is not officially supported as the Pi 5's PCIE is only certified to Gen 2 speeds. Higher frequencies used when Gen 3 speeds are enabled can lead to stability issues. On top of that, the speeds capable through Gen 2 are usually fast enough and the Pi 5 will often be the bottleneck for applications, not the read and write speeds of the drive.

But for those of you wanting to try it, it is easy to enable in the config file. To do so, open a terminal window and punch in:

sudo nano /boot/firmware/config.txt

Then insert in the config file:

dtparam=pciex1_gen=3

Reboot the Pi 5, and you should now be seeing the increased speeds.

To see the gains in using the M.2 HAT, we put the micro SD card and NVME SSD (in Gen 3 and Gen 2 speeds) head to head in some benchmarks. Feel free to benchmark along with your NVME to see how it compares!

Starting with sequential read speeds which we started by installing hdparm with:

sudo apt update

sudo apt install hdparm

And then running the benchmark with:

sudo hdparm -t /dev/nvme0n1

To perform our sequential write tests, we simply ran dd by first navigating to a directory:

cd /tmp

And then running the write tests with:

dd if=/dev/zero of=testfile bs=8k count=50k conv=fdatasync

From our sequential read/write speeds we can see about a 5x increase in storage speeds with the NVME at Gen 2. This is a very welcomed boost in speed as even with the Pi 5's increase in micro SD speeds, its slow read and write speeds are often a limiting factor.

Although we do see nearly a doubling in speed by running the NVME in Gen 3 mode, pure sequential speeds like these are uncommonly used in day-to-day tasks.

To benchmark our 4K random read and write speeds we installed iozone with:

sudo apt update

sudo apt install -y iozone3

And we ran the test with:

iozone -e -I -a -s 100M -r 4k -i 0 -i 1 -i 2 -f /tmp/iozone_testfile

In these tests, we can see an even greater boost in speed over the SD card, with our Gen 2 speeds being roughly 15 times quicker. Gen 3 speeds are also a little bit quicker, but much less of an increase than sequential speeds. These 4k random tests are more indicative of storage performance seen in general day-to-day tasks.