Build Your Image

NetModule provides its own meta layer for customized image generation.

Project Setup

Netmodule Meta Layer

Meta Layer




  • Distribution specfic contents

  • Distribution configurations

  • NetModule image recipes

  • Firmware update tool

  • Disk expansion tool

  • General applications recipes

  • Example local.conf file



  • Distribution specific contents

  • Machine confguration files

  • U-Boot recipes

  • Linux kernel recipe

  • Applications recipes for interface support

  • General low level applications recipes



  • Wlan module firmware

  • Wireless regulatory databases

  • WPA supplicant

  • Wireless tools


Additional Layers and Bitbake

Following additional resources are required:

Setup workspace

Start new build project with cloning all required git repositories:

# Clone the main repo
git clone
cd nm-oem-linux
# Initialize the submodules (meta-layers)
git submodule init && git submodule update

Your workspace should now look similar as in the snippet below:

├── bitbake
├── build
├── env
├── meta-netmodule-bsp
├── meta-netmodule-distro
├── meta-netmodule-wlan
├── meta-openembedded
├── meta-updater
├── openembedded-core

Configure project

To build a yocto image, two base configurations are required: the MACHINE and the DISTRO. Both are provided from the shell environment and can be set by sourcing the required files:

# Choose the OSTree distro
source ./env/distro/ostree-image

# List the available machines with
ls ./env/machine/
# Source the right one
source ./env/machine/hw26

Once both are selected, the bitbake environment will be loaded and ready to build.

Build NetModule reference images

NetModule provides several reference images depends on use case:




Standard reference image. Contains required applications, drivers and tools to use interfaces, network connectivities and sensors.


Based on netmodule-linux-image and extended with helpful development tools for low level access (e.g. direct access on i2c bus) and generic debug tools like strace and gdb.


Minimal ramdisk based image for simple bring up or can be used for emmc operations like device flashing or data recovery.

Images recipes location

Images recipes are located in layer meta-netmodule-distro:


Building with shared state

It is highly recommended to use the yocto shared state from NetModule to speed up build time. Also some closed source tools like “lpa” will only be available through sstate. The sstate will provide already built packages directly from our servers as long as the recipes configurations are the same.

To build using our sstate, make sure that all the layers are matching the submodule hashes from our releases and make sure that the following line is present in your local.conf:

SSTATE_MIRRORS = "file://.*"

Images build instructions

Start image build after sourcing environment with:

bitbake netmodule-linux-image

Images deploy location

Built images are located in deploy directory.::

<project root>/build/tmp/deploy/images/<hw type e.g. am335x-nmhw21>/

If you built an ostree image, you can copy the content of the directory ostree_repo to your http server and continue with Update system with local ostree

cp -r ostree_repo/* /srv/http/ostree_repo

Otherwise you can install the .wic file (full image for the mmc), following the instructions at Image Installation