RPi Fast Reboot

Buildroot

Table of contents

• General info
• Setup
• Configuration
• Build
• Other buildroot commands
• Measurement software for Sleepy Pi 2

General info

An external buildroot project to optimize the localizer project of DistriNet on the Raspberry Pi Zero W. The goal is to improve boot times to prolong running the Raspberry Pi Zero W in combination with a Sleepy Pi 2 on a battery.

Setup

To define the necessary paths (e.g. of buildroot), create a .env file.

cp .env.example .env

Put buildroot source code (from git or a tarball) alongside this project (in ../buildroot), or alter the BUILDROOT_PATH variable in .env.

Configuration

Start configuring the image by first selecting a defconfig.

make rpi0w_defconfig

The optimized configuration is available as rpi0w_fast_reboot_defconfig with all measurement software enabled.

To see all available defconfigs, list them with:

make list-defconfigs

Next, configure the image in menuconfig if required.

make menuconfig

Target packages provided by this project can be found under External options ---> DistriNet.

Build

Build an image (this can take a while):

make all

For a full and clean (re)build, use:

make clean all

When finished, the image to flash on an SD card can be found at output/images/sdcard.img, where output is the folder specified in the .env file.

Other buildroot commands

Any command that buildroot supports can be used. The command will always be passed to buildroot with this project appended to the external tree and the output directory set as configured in .env.

Measurement software for Sleepy Pi 2

The software used to measure the boot time is included at board/distrinet/sleepypi2 and can be flashed with the Arduino IDE. The setup is documented at SpellFoundry. In addition to the Sleepy Pi libraries, the Arduino EDB library is used to store measurements in EEPROM.