Secure DFU OTA for nRF52840 solution modules: Guide to create hex/zip file for implementation - #1(Bootloader)

Here are the guidelines for users to implement Secure DFU OTA(over-the-air) while compiling using nRF52840 Solution modules.

(Click on link for Raytac nRF52840 module series)

IC: nRF52840
DK: PCA10056 (for nRF52840)
SDK: 17.1.0
Softdevice: s140_nrf52_7.2.0_softdevice.hex
IDE: Keil C
PC: Win 10

Below are the following steps to implement Secure DFU OTA by using nRF52840 chip set, SDK17.1.0.
It consists of 3 parts:

Part A: Bootloader

Part B: Application (Click for article link)

Part C: Combining and merging built files (Will be released in the upcoming article after Part B)

In this article, we will be focusing on Part A: Bootloader.

Part A: Bootloader

Path: nRF5_SDK_17.1.0_ddde560\examples\dfu\secure_bootloader\pca10056_s140_ble\arm5_no_packs

Step 1. An error may occur while building bootloader without a public key:
(Shown in red frames in below screenshot)

Step 2. How to generate the public key file in Bootloader?
A. Visit DOS at path: ..\Python27\Scripts
B. Then execute:

nrfutil keys generate private.pem
nrfutil keys display --key pk --format code private.pem --out_file public_key.c

Step 3. Copy the pk[64] code from (public_key.c) into (dfu_public_key.c)
(Shown in red frames in below screenshot)

※Note: Make sure to save the 3 generated files:
private.pem
public_key.c
dfu_public_key.c

Step 4. Generate the bootloader file: nrf52840_xxaa_s140.hex after re-compiling the code files.

※Stay tuned for #2 - Part B: Application in the next article, scheduled release in next week(29/05/2024).

Technical guidelines provided by R&D Manager: Mr. MW Lee
Edited by Sales Manager: Mr. Tony Yin

Raytac Corporation 勁達國際電子股份有限公司  A company of Abietec
Bluetooth & WiFi module maker based on Nordic nRF54, nRF53, nRF52, nRF7002 solution
BT5.4 &BT5.3 & BT5.2 & BT5.1 Qualified, FCC/IC/CE/Telec/KC/RCM/SRRC/NCC Pre-Certified.
Bluetooth Solution: nRF54, nRF5340, nRF52840, nRF52833, nRF52832, nRF52820, nRF52811, nRF52810, nRF52805, nRF51822
WiFi Solution: nRF7002
http://www.raytac.com
email: service@raytac.com
Tel: +886-2-3234-0208