buildroot

get the buildroot submodule,

$ git submodule update --init

built using buildroot LTS tag 2021.02.6.

supported boards

• rpi4 (primary)
• rpi3 (secondary)
• qemu

system packages

on the host system, the minimum build requirements:

• which
• sed
• make >=3.81
• binutils
• build-essential (only for Debian based systems)
• gcc >=4.8
• g++ >=4.8
• bash
• patch
• gzip
• bzip2
• perl >=5.8.7
• tar
• cpio
• unzip
• rsync
• file (must be in /usr/bin/file)
• bc

building

set DEFCONFIG to one of the supported boards,

$ export DEFCONFIG=rpi4

for example. first, configure

$ ./build.sh ${DEFCONFIG}_defconfig

see configuring if you'd like to audit the configuration. then build,

$ ./build.sh

for hardware targets, this builds bootable image ${DEFCONFIG}_output/images/sdcard.img.

emulation

build with DEFCONFIG=qemu and install qemu-system-arm.

$ ./emu.sh qemu_output/

configuring

requries libncurses-dev.

buildroot

$ ./build.sh menuconfig
...  # change some parameters, save
$ ./bulid.sh # rebuild, test things
$ ./build.sh savedefconfig # save those changes, updates corresponding configs `accessilbility-oscilloscope/config/`.

kernel

$ ./build.sh linux-menuconfig
$ ./build.sh linux-savedefconfig
$ ./build.sh linux-update-defconfig

multi-board development

just change the $DEFCONFIG to the current board being developed.