The official Mender documentation explains how Mender works. This is a board-specific complement to the official documentation.

Board description

WaRP7 speeds and eases development of Internet of things and wearable devices by addressing technology challenges and freeing developers to focus on creating differentiated features. The platform consists of a main board and a daughter card. The main board is based on the NXP i.MX 7 Solo applications processor that features an advanced implementation of the ARM Cortex A7 core, as well as the ARM Cortex M4 core.

URL: https://www.nxp.com/support/developer-resources/nxp-designs/warp7-next-generation-iot-and-wearable-development-platform:WARP7

Test results

The Yocto Project releases in the table below have been tested by the Mender community. Please update it if you have tested this integration on other Yocto Project releases:

Yocto Project Build Runtime
sumo (2.5) :test_works: :test_works:
thud (2.6) :test_works: :test_works:
warrior (2.7) :test_works: :test_works:
zeus (3.0) :test_works: :test_works:
dunfell (3.1) :test_works: :test_works:

Build Means that the Yocto Project build using this Mender integration completes without errors and outputs images.
Runtime Means that Mender has been verified to work on the board. For U-Boot-based boards, the integration checklist has been verified.

Getting started


  • A supported Linux distribution and dependencies installed on your workstation/laptop as described in the Yocto Mega Manual
    • NOTE. Instructions depend on which Yocto version you intend to use.
  • Google repo tool installed and in your PATH .

Setup Yocto environment

Set the Yocto Project branch you are building for:

# set to your branch, make sure it is supported (see table above)
export BRANCH="dunfell"  

Create a directory for your mender-nxp setup to live in and clone the
meta information.

mkdir mender-nxp && cd mender-nxp

Initialize repo manifest:

repo init -u https://github.com/mendersoftware/meta-mender-community \
           -m meta-mender-nxp/scripts/manifest-nxp.xml \
           -b ${BRANCH}

Fetch layers in manifest:

repo sync

Next, initialize the build environment:

source setup-environment nxp

NOTE! You need to accept the Freescale EULA at ‘…/sources/meta-freescale/EULA’. Please read it and in case you accept it, add:


in your local.conf.

Building the image

You can now proceed with building an image:

MACHINE=imx7s-warp bitbake core-image-base

Replace core-image-base with your desired image target.

Using the build output

  • tmp/deploy/images/imx7s-warp/core-image-base-imx7s-warp.sdimg
  • tmp/deploy/images/imx7s-warp/core-image-base-imx7s-warp.mender
  • tmp/deploy/images/imx7s-warp/u-boot-dtb.imx

The disk image (with .sdimg suffix) is used to provision the device storage for devices without Mender running already.

The u-boot.imx file is used to provision the device with a Mender compatible U-Boot.

On the other hand, if you already have Mender running on your device and want to deploy a rootfs update using this build, you should use the Mender Artifact files, which have .mender suffix. You can either deploy this Artifact in managed mode with the Mender server (upload it under Releases in the server UI) or by using the Mender client only in Standalone deployments.

Flash instructions

Based on the output artifacts described above we need to flash the u-boot.imx and core-image-base-imx7s-warp.sdimg separately to fully provision an device and for it to work with Mender.

Required software on the host PC:

Setup WaRP7 for loading U-Boot
  • Remove the CPU board from the base board then put switch 2 in the upper position
  • Reconnect the CPU board to the base board
  • Connect a USB to serial adapter between the host PC and WaRP7 (USB port on the base board)
  • Connect a USB cable between the OTG WaRP7 port and the host PC (USB port on the CPU board)

Clone imx_usb_loader:

git clone https://github.com/boundarydevices/imx_usb_loader

Change directory to imx_usb_loader:

cd imx_usb_loader

Copy u-boot-dtb.imx which was part of the Yocto/OE-core build output to imx_usb_loader

cp mender-nxp/build/tmp/deploy/images/imx7s-warp/u-boot-dtb.imx .

Open a terminal program such as microcom:

sudo microcom --port=/dev/ttyUSB0 --speed=115200

Transfer u-boot.imx to RAM and execute it. NOTE! This requires you to halt the boot process in U-Boot otherwise it will continue with the normal boot flow and requires a level of swiftness since the bootdelay is only 3 seconds:

sudo ./imx_usb u-boot-dtb.imx

Then U-Boot should start and its messages will appear in the console program.

Use the default environment variables:

=> env default -f -a
=> saveenv

Run the DFU command:

=> dfu 0 mmc 0

Transfer u-boot.imx that will be flashed into the eMMC:

sudo dfu-util -D u-boot-dtb.imx -a boot

The following message should be seen on the U-Boot prompt after a successful upgrade:

Ctrl+C to exit …​

Remove power from the WaRP7 board.

Put WaRP7 board into normal boot mode (put the switch 2 in the lower position)

Power up the board and the new updated U-Boot should boot from eMMC

Setup to update the image (.sdimg)

From U-Boot side:

=> ums 0 mmc 0

From Host side:

sudo dd if=core-image-base-imx7s-warp.sdimg of=/dev/sdX bs=1M && sudo sync

That is it, you can now power-cycle or reset the device and you should have
a Mender compatible image running on your device with the Mender client.


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