How to Boot Raspberry Pi 4 / 400 From an SSD or Flash Drive

A firmware update lets you use any USB device to boot a Raspberry Pi 4 / 400.

The fastest USB storage options for Raspberry Pi

It took me 2 months to boot CM4 from NVMe - NotEnoughTech

Pi400 Ubuntu Node Setup Guide

Boot Ubuntu Server 22.04 LTS from USB SSD on Raspberry Pi 4

Raspberry Pi 400 SSD Upgrade - Raspberry Pi Spy

The fastest USB storage options for Raspberry Pi

Raspberry Pi 4 With an SSD: Dramatic Speed Improvements, Higher

Raspberry Pi 400 Alternate Bottom with 2.5 SSD Mount. by jispal01

Turbo-charge Raspberry Pi 400 with an M.2 SATA SSD drive

Raspberry Pi 3 With Bootable SSD Drive : 10 Steps - Instructables

Switch from SD card to SSD for Home Assistant on a Raspberry Pi 4

boot_usb_rpi_only [Batocera.linux - Wiki]