Raspberry Pi USB Boot Mode

About Boot Mode

The Raspberry Pi 3 can now be booted from a compatible USB drive. It works pretty well, but there are no noticeable differences in speed between a good SD card and a good USB drive. Primarily, cost may be a factor, as good USB drives are generally cheaper than good SD cards. Not all USB drives are supported–my Sandisk Ultra Fit worked, but my Trancend JetFlash did not.

Read the official documentation to learn how to set it up.


Boot Mode and Updates

I used apt-get update/upgrade to update my Raspberry Pi, which wiped out the boot mode. Make sure not to upgrade the bootloader, or save an edited bootable sd card to reapply the boot mode edits.


sudo mkdir /mnt/target
 sudo mount /dev/sda2 /mnt/target/
 sudo mkdir /mnt/target/boot
 sudo mount /dev/sda1 /mnt/target/boot/

cd /mnt/target
 sudo mount --bind /dev dev
 sudo mount --bind /sys sys
 sudo mount --bind /proc proc
 sudo chroot /mnt/target

sudo BRANCH=next rpi-update

 sudo umount dev
 sudo umount sys
 sudo umount proc

sudo reboot

Official forums also have some more information.