# Use BuildRoot to build a Raspberry Pi image

## Linux tools comparison

1. BuildRoot
i. Easy to use
ii. Limited configuration settings
iii. Requires full image rebuild


2. OpenWrt
i. Focused on networking gear(e.g. routers)
ii. Package-based updates.


3. Yocto
i. Steep learning curve
ii. Customizable
iii. Active community


---

## Let start to build the first linux image

### Devices:
Host: **Ubuntu 22.04.3 desktop amd64**
Target machine: **Raspberry Pi 4b**

- #### Install some required packeges

sudo apt-get install build-essential
sudo apt-get install libncurses5-dev libncursesw5-dev

- #### Make a project directory

mkdir projects
cd projects/

- #### Run the commands below to ensure the all packages are latest

sudo apt update
sudo apt upgrade

- #### Once that's done, we'll need to clone BuildRoot project, and then go into the BuildRoot folder

git clone git://git.buildroot.net/buildroot
cd buildroot/

- #### Construct .config file

make ${your config file}

- #### Call a graphical interface to adjust the options for the build

make menuconfig

This is how you would make changes to things like your kernel or adding packages prior to building the linux image. My configuration is as following:

- System configuration -> System hostname ->
- ${enter your own host name}
- System configuration -> System banner ->
- ${enter your own banner}
- System configuration -> Root password ->
- ${enter your password}
- Target packages -> Networking applications
- [*] OpenSSH
- [*] crda
- [*] wpa_supplicand
- [*] Enable autoscan
- [*] Install wpa_passphrase binary
- [*] Enalbe support for the DBus control interface
- System configuration -> /bin/sh ->
- (select **bash**)

- Target packages -> Interpreter languages and scripting ->
- [*] python3

- Target packages -> Shell and utilities ->
- [*] sudo

- Target packages -> System tools ->
- [*] htop
- Target packages -> Text editors and viewers ->
- [*] nano
- [*] vim
- Filesystem images -> exact size
- 200M

make

It will taka for a while. It could take one or more hours in order to build the image

The make command will generally perform the following steps:

- download source files (as required);
- configure, build and install the cross-compilation toolchain, or simply import an external toolchain;
- configure, build and install selected target packages;
- build a kernel image, if selected;
- build a bootloader image, if selected;
- create a root filesystem in selected formats.

- #### After that, you can check your output files

ls -la output/images/

- #### Next, download Raspberry Pi Imager on your host. Open the app click **Choose Os** and select the **Use custom** option. Subsequently, choose sdcard.img you just builded.

- #### Then, choose your SD card and start to write in.

#### After that, you can remove your SD card and try to boot your Raspberry Pi