Building Embedded System

There are two build systems that can be used to build images embedded systems using linux.

• Yocto.
• Buildroot.

Tool to help the build

• Using Devtool to Streamline Your Yocto Project Workflow - Tim Orling, Intel

Raspberry pi

The official raspbian o/s is built with Buildroot, but there is also Yocto based builds available,

• Building 32-bit Raspberry Pi Systems with Yocto.
• Building 64-bit Systems for Raspberry Pi 4 with Yocto
• Building embedded GNU/Linux distribution for Raspberry Pi using the Yocto Project.

If you want to switch init system, you can check existing init system by using sudo stat /sbin/init.

Cross compile raspbian

• Making a Raspbian Cross Compilation SDK
• Kernel building.
• Devicetree on the Raspberry Pi.

Yocto with wsl2

• WSL2 file permission issues cause Buildroot and Yocto build failures.
• WSL2 ram usage problem workaround.
• WSL2 ram usage.
• WSL2 ram usage.
• WSL2 global options.
• Yocto mega manual

wsl2 for cross compile

the default mounts for wsl2 ubuntu ext4 is C:\Users\<username>\AppData\Local\Packages\Canonical*\LocalState\ext4.vhdx. Often time we require multiple instances to work on separate ext4 mount on a different drive for disk space or other reasons.

First check the distro name.

C:\> wsl -l -v
  NAME            STATE           VERSION
* Ubuntu-20.04    Running         2

The distro name is Ubuntu-20.04.

Now we need to set the default user via editing /etc/wsl.conf.

[user]
default=<username> 

Now we will create another image which is a copy of the Ubuntu-20.04.

PS C:\> wsl --shutdown
PS C:\> wsl -l -v
  NAME            STATE           VERSION
* Ubuntu-20.04    Stopped         2
PS C:\> cd d:\
PS D:\> mkdir my_wsl
PS D:\> cd my_wsl
PS D:\my_wsl> wsl --export Ubuntu-20.04 my_distro.tar
PS D:\my_wsl> wsl --import my_distro my_distro my_distro.tar
PS D:\my_wsl> wsl -l -v
  NAME            STATE           VERSION
* Ubuntu-20.04    Stopped         2
  my_distro       Stopped         2

Now we have distro on D drive.

We can create a VHDX file using windows 10 Computer Management tool. The we can detach it. We have to figure out a way to initialize the file as ext4 and mount to a wsl2 linux distro.

Manually download wsl2 distro

Use download page to get distro. It downloads a .appx file which can be opened by 7zip and extract install.tar.gz. now we can use wsl command to install it,

wsl --import my_distro my_distro install.tar.gz

yocto devtool

• Yocto Project® devtool Overviewand Hands-On, slides.
• Using Devtool to Streamline Your Yocto Project Workflow - Tim Orling, Intel.
• Yocto Project Extensible SDK: Simplifying the Workflow for Application Developers.
• Working with the Linux Kernel in the Yocto Project.

yocto tutorials

• Live Coding with Yocto Project.