Compiling Buildroot from scratch

Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation. This article illustrates how to generate a ready-to-use microSD image from scratch using the Buildroot scripts and utilities to download the sources of any code, compile them and generate a fully working microSD.

This article was written using a Linux Ubuntu 22.04.2 LTS. It is advisable to use an USB to 3V TTL serial cable or a DPI interface to have access to the debug port.

Install on your Linux PC the requested packages listed here:

http://buildroot.uclibc.org/downloads/manual/manual.html#requirement-mandatory

Open a command line and download Buildroot from the official web site:

$ wget https://buildroot.org/downloads/buildroot-2024.02.1.tar.gz
$ tar -xvf buildroot-2024.02.1.tar.gz
$ cd buildroot-2024.02.1

Create a git repository:

$ git init ; git add . ; git commit -m "vanilla" ; git branch acme ; git checkout acme

Download the patch for the Acme board you have (just one):

$ wget https://www.acmesystems.it/www/buildroot/acme.patch

Apply the patch:

$ patch -p1 < acme.patch

And set the configuration you need:

$ make foxd27_defconfig

The available configurations are:

arietta_defconfig
foxd27_defconfig
foxd27-h10cu_defconfig
foxd27-bot_defconfig

Launch the compilation:

$ make

This operation will take about 1 hour to download and compile any sources.

If all went well you will obtain this file in output/images directory:

sdcard.img

Install new packages

To install new packages from the menuconfig menu type:

$ make menuconfig

Then repeat the procedure to generate the new microSD image from Make command.

Regenerate the target directory

$ rm -rf output/target
$ find output/ -name ".stamp_target_installed" -delete
$ rm -f output/build/host-gcc-final-*/.stamp_host_installed

Change the Linux Kernel configuration

$ make linux-menuconfig
$ make linux-rebuild
$ make

Save the kernel config

$ make linux-savedefconfig

File used:

acme.patch

Download ready-to-use microSD images for your boards

Arietta
Buildroot 2024.02.1, Kernel 6.1, At91Boostrap 3.10.4, lighttpd, Python3, RNDIS drivers

Fox Board D27
Buildroot 2024.02.1, Kernel 6.1, At91Boostrap 3.10.4, lighttpd, Python3

Make the microSD

Download and install the free tool Balena Etcher available for any platform to write the microSD using the filename.img generated by scratch od downloaded:

https://www.balena.io/etcher/

Insert the microSD generated in your board and use the debug port to check the boot messages and get the access to the Linux prompt.

!! SECURITY WARNING !!

By default, only the root user is defined, and no password is requested at login, both on the debug port and on SSH access. This is because this image is intended for educational and experimental use only. Don't release your products with this image as is.

Partition resizing

Type this command to check how is partitioned the microSD

$ parted /dev/mmcblk0 --script print

Model: SD SS08G (sd/mmc)
Disk /dev/mmcblk0: 7948MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type     File system  Flags
 1      512B    16.8MB  16.8MB  primary  fat16        boot, lba
 2      16.8MB  101MB   83.9MB  primary  ext4

To resize the root partition to fill the entire microSD type:

$ parted /dev/mmcblk0 --script resizepart 2 100%
$ resize2fs /dev/mmcblk0p2

Check it again:

$ parted /dev/mmcblk0 --script print

Model: SD SS08G (sd/mmc)
Disk /dev/mmcblk0: 7948MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Products related

Features Index Buy

Linux System On Module

CPU Microchip AT91SAMG25
ARM9 @ 400 MHz
Armel architecture
DDR2 RAM 128/256 MB
Size: 53x25 mm
Plug-in module
40 pins 2.54 mm pitch
Boot from uSD
Linux Kernel 5.15 LTS
Debian, Buildroot and Yocto Linux
Fully open source drivers