Booting a Raspberry Pi From USB (No SD Card Needed)

by ElectroScope Archive in Circuits > Raspberry Pi

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Booting a Raspberry Pi From USB (No SD Card Needed)

How-to-Boot-Raspberry-Pi-from-USB.png

After spending enough time with Raspberry Pi projects, an SD card is bound to betray you. Maybe it was corrupted after a power cut. Maybe it just wore out after too many log writes. Either way, it sucks. That’s why I finally ditched SD cards for good and started booting my Pis straight from USB.

Good news? It’s faster, more reliable, and way less headache. And depending on which Pi you’ve got, the process ranges from “just works” to “okay, a little fiddly but worth it.”

This guide covers Pi 3B, Pi 3B+, Pi 4, and the shiny new Pi 5.

Why Even Bother With USB Boot?

SD cards are fine for blinking LEDs and small projects. But they wear out, and they’re slow. The Pi 4’s SD interface tops out around 50 MB/s, and older models are even slower. Compare that to a USB 3 SSD where I got ~200 MB/s reads. The difference is huge.

Apps install faster, file operations don’t drag, and the whole OS feels more like a “real” computer.

Supplies

  1. A Raspberry Pi (3B, 3B+, 4, or 5)
  2. A decent USB stick or even better, a USB SSD
  3. A microSD card (only needed for Pi 3B or initial setup on Pi 4)
  4. Raspberry Pi Imager (download it here: https://www.raspberrypi.com/software/)
  5. Keyboard, monitor, and some patience

Raspberry Pi 3B - the One-Time Unlock

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The Pi 3B doesn’t boot from USB out of the box. You need to flip a hidden switch in its One-Time Programmable (OTP) memory. Sounds scary, but it’s just a one-liner.

  1. Flash Raspberry Pi OS onto an SD card and boot it.
  2. Open Terminal and run:

echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt
sudo reboot
  1. After reboot, check if the flag was written below. If you see 17:3020000a, congrats, USB boot is unlocked forever.

vcgencmd otp_dump | grep 17:
  1. Flash Raspberry Pi OS to a USB stick, plug it in, yank the SD card, and reboot. Boom, USB boot.


Raspberry Pi 3B+ - Easy Mode

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This one’s simple. USB boot works right out of the box.

  1. Use Raspberry Pi Imager to flash Raspberry Pi OS onto a USB stick.
  2. Plug it into the Pi 3B+.
  3. Power it on.

That’s literally it.

Raspberry Pi 4 - the EEPROM Dance

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The Pi 4 stores its bootloader in EEPROM, which means you can update it and tweak the boot order. Some Pi 4s need an update to prioritize USB boot.

Option A: Command line way

  1. Boot from an SD card, open Terminal.
  2. Update everything:

sudo apt update
sudo apt full-upgrade -y
sudo rpi-eeprom-update -a
  1. Run:

sudo raspi-config
  1. Then go to: Advanced Options → Boot Order → USB Boot.
  2. Reboot, remove the SD card, and boot from USB.


Raspberry Pi 5 - Out of the Box

This one doesn’t mess around. USB boot and even NVMe boot are supported right out of the gate.

  1. Flash Raspberry Pi OS to a USB SSD.
  2. Plug it into one of the blue USB 3.0 ports.
  3. Power on. That’s it.

Bonus: If you want insane speeds, use the PCIe slot with an NVMe adapter. It’s like turning your Pi into a mini desktop PC.

Should You Do It?

If you’re tired of random SD card deaths and want your Pi to feel snappier, absolutely. For servers, media centers, or anything that runs 24/7, a USB boot is a no-brainer.

For quick weekend projects? SD cards are fine. But trust me, once you go USB boot, you won’t look back.

This guide is a simplified version of: Boot Raspberry Pi from USB