Yocyo-raspi

Simple, minimal example on building custom Raspberryp 5 images. Produces an image with a very simple distro with systemd, and console interface.

Usage

1. Open folder in dev container.
2. source /yocto/poky/oe-init-build-env.
3. Add this layers with bitbake:

• bitbake-layers add-layer /yocto/workspace/meta-simple/
• bitbake-layers add-layer /yocto/workspace/meta-raspberrypi

4. Change build/local.conf file:

• Add MACHINE ?= "raspberrypi5" for raspberry image or any qemu.
• Add DISTRO ?= "myimg" for the custom distro.

NOTE: If problem downloading kernel occurs, look into the log for the git command and simply run it from a terminal manually.

Config

At local.conf:

• Add more packages with: IMAGE_INSTALL:append = " <packages> ...

Build

• bitbake my-img

Qemu

If a qemu machine was chosen, use (from dev container):

• runqemu slirp nographic

Deploy

If you produce an image for a Raspberry board, make sure you copy them out of the container:

• docker cp <container_id>:/yocto/build/tmp/deploy/images/<machine>/<image>.wic.gz . Example: docker cp -L a7ac:/yocto/build/tmp/deploy/images/raspberrypi5/my-img-raspberrypi5.rootfs-20240619160220.wic.bz2 .

Then, extract to disk. Example:

• bzip2 -cd my-img-raspberrypi5.rootfs-20240619160220.wic.bz2 | sudo dd of=/dev/disk5 bs=10M status=progress

Access

The machine should be SSH accessible from a static ip: 192.168.1.10. Make sure the host device has an IP in range.

Wifi Hotspot

• https://wiki.somlabs.com/index.php/Connecting_to_WiFi_network_using_systemd_and_wpa-supplicant
• Wifi is disabled at boot by default. Once logged in, simply type systemctl enable wpa_supplicant@wlan0
• See https://lists.yoctoproject.org/g/yocto/topic/enable/61338089
• Details: https://man.archlinux.org/man/systemd.network.5

Wifi client

• After image is deployed, change ssid and psk fields of /etc/wpa_supplicant/wpa_supplicant-wlan0.conf and restart wpa_supplicant service.

Kernel modifications

• https://wiki.koansoftware.com/index.php/Modify_the_linux_kernel_with_configuration_fragments_in_Yocto
• https://docs.yoctoproject.org/kernel-dev/index.html#:~:text=Table%20of%20Contents.%201%20Introduction.%201.1
• bitbake -c menuconfig virtual/kernel

SWUpdate ( Work in progress )

.swu files are generated when installing swupdate package. To update from within the system, use this as reference:

• swupdate -i my-img-raspberrypi5.rootfs.swu -H a:1.0 -v -e stable,copy1