Adding a New Application to RDK-7 RPi4 Build

With the latest RDK-7 release, the various software layers, like Application, Middleware, OSS, and Vendor layers are separated. This brings some additional complexities of building and combining multiple layers using an assembler layer into a single package, but it also speeds up the builds by needing to build only the layers that require modification.

In this post we will explore how to add a new application to an RPi4 RDK-V build. The guide requires that the build machine has already configured RDK credentials (.netrc/ssh access). You also need an SD Card with at least 8GB capacity and a Raspberry Pi 4.

Setup the Build Environment

Clone the non-official RDK-7 docker build scripts and setup your container environment:

git clone https://github.com/zoltan-ongithub/rdk7-docker-builder
cd rdk7-docker-builder/
./rdk7-docker.sh setup    # Type to setup the "application" layer
./rdk7-docker.sh sync     # Sync the source code

Add a New Application

Let's add a new application to the application layer:

mkdir application-layer/rdke/application/meta-application-rdke-dev/recipes-thirdparty/guessing-game/

Edit

application-layer/rdke/application/meta-application-rdke-dev/recipes-thirdparty/guessing-game/guessing-game.bb

in your favorite editor and add a new recipe:

SUMMARY = "RDK application to showcase rdkservices"
SECTION = "rdk/samples"
LICENSE = "Apache-2.0"
LIC_FILES_CHKSUM = "file://${S}/LICENSE;md5=387be95ea3370b9ae768c395d4eeaeea"

SRC_URI = "git://github.com/zoltan-ongithub/lightning-guessing-game;protocol=https;branch=main"

SRCREV = "${AUTOREV}"
S = "${WORKDIR}/git"

PACKAGE_ARCH = "${APP_LAYER_ARCH}"

#Lightning application, no need for configuration/compilation
do_compile[noexec] = "1"
do_configure[noexec] = "1"
do_patch[noexec] = "1"

RDEPENDS:${PN}-dev = ""

do_install() {
   install -d ${D}/home/root/guessinggame
   cp -r ${S}/* ${D}/home/root/guessinggame
}

FILES:${PN} += "/home/root/*"

In application-layer/rdke/application/meta-application-rdke-dev/recipes-core/packagegroups/packagegroup-application-layer.bb

add the guessinggame to packagegroup-application-layer section to ensure the package is built into the final image.

Build the Application Layer

./rdk7-docker.sh run

Assemble All Layers

Now let's switch to the assembler layer and assemble all the layers:

./rdk7-docker.sh setup

When asked, choose 'local' for application layer. This will ensure that your local application layer will be used instead of the prebuilt remote packages. See the note below on layers for explanation.

Build the Full Stack Image

Build the full stack image:

./rdk7-docker.sh run

The final image will be:

./image-assembler-layer/build-raspberrypi4-64-rdke/tmp/deploy/images/raspberrypi4-64-rdke/lib32-rdk-fullstack-image-RPI4-20251118092409.rootfs.wic

You can flash it using dd or Balena Etcher.

Note on Layers

Building a layer publishes the packages to a local IPK repository ~/community_shared. When the final full stack layer is combined, the packages can be pulled from the local repository or from the remote pre-built repository.