ota_mcuboot_client_wifi

Overview

This application demonstrates an HTTPS OTA client using FreeRTOS + LWIP + MbedTLS + CoreHTTP. The client connects to a HTTPS server and requests an OTA binary for download and subsequent installation by MCUBoot.

Supported Boards

Prepare the Demo

  1. The demo requires MCUBoot bootloader to be present in the FLASH memory to function properly. It is recommended to build and program the bootloader first, then go on with the application. Please refer to respective readme of the mcuboot_opensource example and follow the steps there before you continue.

  2. Go through setup files in the demo source tree ota_config.h and network_cfg.h to check:

    • use of DHCP/static IP

    • Default HTTPS server IP and port

    • Default OTA image file path on the server

  3. Before building the example application select Wi-Fi module macro in the app_config.h. (see #define WIFI_<SoC Name>BOARD<Module Name>). For more information about Wi-Fi module connection see coresponding readme in WiFi examples directory.

  4. Connect a USB cable between the PC host and the OpenSDA (or USB to Serial) USB port on the target board.

  5. Open a serial terminal on PC for connected board with these settings:

    • 115200 baud rate

    • 8 data bits

    • No parity

    • One stop bit

    • No flow control

    • Unix line ending using \n

  6. Install WiFi connectivity module into SD or M.2 slot if needed.

Running the HTTPS server example

For better experience there is a simple HTTPS server Python3 implementation attached to this example. It was tested with both Windows and Linux, however, it will run on anything supported by Python3.

The directory https_server has the following content:

  • certs - directory containing a private key and server certificate signed by mbedtls test_ca (found in mbedtls source)

  • httpsd_ota.py - https server code

When run with no parameters it creates a server instance on port 4433:

python3 httpsd_ota.py

With the server code running it is now possible to create connections to this server and request files located in its directory. After the ota image is generated and signed, the last step is to copy it to the server directory.

Running the demo

To get the application properly executed by the bootloader, it is necessary to put signed application image to the primary application partition. There are multiple options how to achieve that, however in principle the are two main methods (both presuming the bootlaoder is already in place):

  1. programing signed application image to the primary application partition using an external tool (direct method)

  2. jump-starting an unsigned application by a debugger, performing OTA update with the signed image, resetting the board and letting the bootloader to perform update (indirect method)

The latter method is described step by step below:

  1. Open the demo project and build it. Known issue: MDK linker issues warning about unused boot_hdr sections. This does not affect the functionality of the example.

  2. Prepare signed image of the application from raw binary as described in the mcuboot_opensource readme.

    • In case of MCUXpresso raw binary may not be generated automatically. Use binary tools after right clicking Binaries/.axf file in the project tree to generate it manually.

  3. Copy the signed image on your HTTPS server and make sure it’s running. Default image path defined in the client is /ota.bin.

  4. Launch the debugger in your IDE to jump-start the application.

    • In case of MCUXpresso IDE the execution stalls in an endless loop in the bootloader. Pause the debugging and use debugger console and issue command jump ResetISR.

  5. When the demo runs successfully, the terminal will display message that coresponds with the following:

    OTA HTTPS client demo (WiFi)

Initializing WiFi connection...
MAC Address: 00:50:43:02:FE:01
Successfully initialized WiFi module

Copyright  2022  NXP

$

  6. The demo is now waiting for user input. Use help to see all available commands.

  7. To connect to WiFi network. First use wifi conf command to setup network name and password. Then wifi join to connect.

  8. When connected and with HTTPS server runnning an OTA image is downloaded using ota command:

     $ ota 0 /ota.bin 192.168.1.10 4433

    This creates a secure connection to specified server 192.168.1.10 using port 4433 and request file stored at path /ota.bin. The downloaded data will be stored into secondary slot for image 0. Note that it depends on the used platform how many images it uses (see ‘image info’ command for details).

  9. After succesfull download of an OTA image, the command image info can be used to inspect the change in the secondary image slot:

     $ image info
 Image 0; name APP; state none:
   Slot 0; slotAddr 8020000; slotSize 655360
     <IMAGE APP_PRIMARY: size 373268; version 1.22.0.0>
   Slot 1; slotAddr 8210000; slotSize 655360
     <IMAGE APP_SECONDARY: size 384238; version 2.20.0.0>

  10. Now the downloaded image needs to be set as ReadyForTest to inform the bootloader about a new image to be installed and tested upon next reboot:

    $ image test 0

    This change is reflected in the image state parameter set as ReadyForTest in the image info command output.

  11. To trigger installation of new image either reboot the board manually or use reboot command.

  12. After new image is installed and booted, again use the image command to make sure new version of the image is now active and the image state is now set as Testing.

  13. Since the image now happens to be in the Testing state, it needs to be accepted with image accept command:

    $ image accept 0

    This makes sure that upon next reboot the image won’t be reverted to its previous version.