Pi USB Boot Switcher

Introduction

Installation of Raspbian (or other similar distributions) on a SD-card is easy and straightforward. In contrast running the system directly from the SD-card is not optimal, especially if you have a lot of I/O-operations. A solution to the problem is to copy the installation to an usb device, typically a HDD or SSD, but an usb-stick will also boost performance (unless you happen to have a really slow one).

To run a system from an USB device, you have two options:

• Keep the boot partition with firmware and kernel on the SD-card, but move the system partition (also called root partition) to the usb device. This solution works with all available models.
• use usb boot. This is a new feature available with a Pi3. In this case the boot partition will also reside on the usb device and you don't need a SD-card at all. This only works with a Pi3 and even then not every usb device supports the operation.

The pi-boot-switch-script supports both options. The script allows you to

• copy your root-partition from the SD-card to SD-card.
• copy your root-partition from the SD-card to the usb device.
• copy your root-partition from and to directories
• copy your boot-partition from the SD-card to the usb device.
• switch between multiple systems (a sort of bootmanager).
• install new images directly to a target-partition.

For a quick walkthrough read the document doc/simple-usage.md.

Installation

To install the script, just run

git clone https://github.com/bablokb/pi-boot-switch.git
sudo tools/install

This just installs the script in files/usr/local/sbin/pi-boot-switch to /usr/local/sbin/pi-boot-switch.

Documentation

After installation, Raspbian usually expands it's root-filesystem and claims all available space on the SD-card. A prerequisite for pi-boot-switch is free space, so you have to shrink the filesystem and partition to regain some of it. How to do that is covered in the document doc/shrink-rootsystem.md.

You can find a complete walkthrough of the most important options in the tutorial doc/simple-usage.md.

Installing an additional image using the option -i is covered in doc/image-install.md.

Options not covered in these documents are either not yet implemented, or for special use. Please check the code before using them.

For a short help just run

$ > sudo pi-boot-switch -h

pi-boot-switch: manage Raspberry Pi multiboot system
  
usage: pi-boot-switch [options]
  Possible options:

    -I             show partition info

    -c             copy current partition (select target with -t)
    -t dest[=name] target partition/dir (required for -i or -c, e.g. '-t /dev/sdc')
    -C other       copy from another partition/dir (select target with -t)
    -S             target partition is on a SD-card, not an usb-device
    -F             format target partition
    -k             keep existing /home on target during copy (don't use -F)
    -U             use UUIDs instead of device-names

    -L label       set label of target partition (also available standalone)
    -D descr       set description of target partition (also available standalone)

    -B             copy /boot to partition dest and set dest as new /boot

    -s             switch to partition dest for next boot (requires reboot)
                   (select target with -t)
    -u             update /home on dest from current partition before switching
    -R             reboot immediately after switching

    -i image       install image to target partition

    -v             verbose operation
    -h             show this help

Armbian support

Pi-boot-switch now also supports Armbian. Since Armbian uses a single partition for both the boot and root filesystem, you first have to convert the image. You can download a suitable script from my armbian-convert project. This project contains a single file armbian_convert.sh, which will convert a typical armbian 7z-image with a single partition to an image with two partitions (one for boot and one for root).

Once converted, you can install the image like any other image with e.g. dd to your sd-card and use it with pi-boot-switch to switch between partitions.

Armbian uses UUIDs for referencing the root-device within /boot/armbianEnv.txt. The option -U will keep the UUIDs, without this option newly copied partitions will use device names. This does no harm but is not the Armbian way of doing it.

Extlinux.conf support

Like Armbian, most extlinux environments use UUIDs for referencing the root-device within /boot/extlinux/extlinux.conf. The option -U will keep the UUIDs.