Booting A Raspberry Pi From USB
A Raspberry Pi can be booted from a USB drive. This is helpful if you have a really fast USB SSD drive.
Ensure your bootloader firmware is dated Sep 3 2020 or later.
pi@raspberrypi:~ $ vcgencmd bootloader_version Sep 3 2020 13:11:43
Ensure your OS version is 2020-08-20 or later.
pi@raspberrypi:~ $ cat /etc/rpi-issue Raspberry Pi reference 2020-08-20
If that all checks out, image a hard drive just like how you would an SD card. For example, Balena Etcher can image a USB hard drive instead of an SD card. After it is imaged, connect the drive to a USB3 port and power on the Pi.