Raspberry Pi 2, 3, 4, 5 USB SSD or USB drive boot

Updated 2024-06-06 !

After having tested several methods creating a bootable USB SSD, or other USB drive, for Raspberry Pi(RPi) 3 4 and 5, I finished with this simple method

• Create the setup you want on a ordinary SD card(Or use existing)
• Make a bootable backup/clone of the SD card saving it to the USB SSD
• Remove the SD card and boot from the USB SSD

Having a RPi 4, 5 ? Use this post on how to write the OS direct to the SSD.

 

Prerequisites

The tests was made with this SSD

If You are starting from scratch with a new SD card you can check these instructions to install the RPi OS and after that you install your selected software.

Please note !!! Before you continue you MUST update/upgrade !! to get the latest OS/firmware

sudo apt update && sudo apt full-upgrade -y && sudo apt clean

Check out the clone alternatives att Extra below !

Setup

Raspberry Pi 3(RPi3)

Sometimes you find excellent "how to" posts and this one is such, explaining how to set up the RPi3 for SSD boot. Thanks "HawaiianPi" ! (Here you also find some hints for RPi 2)

On my RPi 3, 7 years old, I had to set the OTP bit and add 

program_usb_boot_mode=1 

program_usb_boot_timeout=1

to "config.txt",  sudo nano /boot/firmware/config.txt (Older RPi OS? => sudo nano /boot/config.txt, and reboot to make it work. (After the reboot, check if the 2 added lines are still there, otherwise delete them.)

Also please check the issue below with high CPU load due to the RPi 3 is polling the SD card !!

Raspberry Pi 4, 5

Run the command

sudo raspi-config

and then select "6 Advanced options => A4 Boot order => B2 NVMe/USB Boot"

This isn't really mandatory since the RPi will check all 3 ways but selecting makes the boot quicker.

Common instructions

Insert the USB SSD and then follow the instructions for a backup/clone of the SD card to the USB SSD

Copy alternatives are found at Extra, below!

Power down the RPi

sudo shutdown now

disconnect the power and remove the SD card. Connect the power again and the RPi will boot from the USB SSD.

If you do updates to the USB SSD I recommend to make a backup with the backup program to a SD card. Probably the boot disk will be named "sda" and the inserted, in a USB port, backup SD card will be named "sdb" so the command will be 

sudo rpi-clone sdb -f

RPi 5 boot problem

USB boot is disabled by default when connected to a 3A power supply so you must use a proper power supply, and power cord, that have at least 5 Amp capacity. Another way is to edit "config.txt",  sudo nano /boot/firmware/config.txt and add "usb_max_current_enable=1" at the end of the file.

Speed test

A speed test is made available by the RPi guys. This software can be used to compare the SD card speed with your installed USB drive. Install with 

sudo apt install agnostics

and run from the GUI or from command line, (inspiration link), with

sudo sh /usr/share/agnostics/sdtest.sh

Another way is using the command (Inspire link)

dd if=/dev/zero of=./speedTestFile bs=20M count=5 oflag=direct

which will create and copy a file, speedTestFile, and report the write speed. Go on with reading the file with 

dd if=./speedTestFile of=/dev/zero bs=20M count=5 oflag=dsync

and get the read speed. Then delete the file with rm speedTestFile

High CPU load on a RPi 3 ?

I detected that the CPU load on my RPi 3, booting from the SSD, was over 15 %, used the "top" command, even when the RPi 3 didn't do anything ?? Did some googling and found this which helped. In short, add "dtparam=sd_poll_once" to "/boot/config.txt"

Extra

Clone alternatives

• Use the standard "Accessories => CD Card Copier" found in the RPi meny. (If you don't use RPi OS lite) If not installed ? sudo apt install piclone
• After a format of the USB drive use "dd if=/dev/mmcblk0 of=/dev/sda status=progress" and after the boot, from the USB drive, expand the filesystem via "sudo raspi-config", 6, A1. Please note that this only works if the target has a bigger storage than the source and that the command will copy the whole source SD card which will take longer time than the recommended clone above.

Check out this post connecting RPi to external storage/disk

Checking USB boot bit

Use command(Not RPi 4,5)

vcgencmd otp_dump | grep 17:

The output could be 17:3020000a. If there is a 1, where the 3 is, USB boot is not enabled.

Boost read/write speed without SSD

Instead of using the standard SD card, or a SSD, you could use a USB flash card with high read speed. Just follow the instructions above as if it was an SSD.

RPi 4, 5

Info regarding Raspberry Pi boot EEPROM update is found here, 

but the best way is just to run

sudo apt update && sudo apt full-upgrade -y && sudo apt clean

mentioned above.