How to reflash the bootloader on a Fly-CDYv3

Overview

This page covers how to reflash the bootloader on a Fly-CDYv3.

Tools

Unfortunately, it is not possible to enter DFU mode on this board through USB.
This means that you will need an ST-Link to be able to reflash the bootloader. Fortunately these have been cloned by chinese manufacturers and can be picked up cheaply.

Software

These instructions cover flashing with Windows using the STM32CubeProgrammer software. It is possible to use other software, such as DFU-Utils on linux, but they aren’t covered here. You will have to register to be able to download the software.

Wiring

Connect the ST-Link to the Fly-CDYv3 using 5 Jumpers. Connect the following:

Fly-CDYv3 ST-Link
RST RST
SWDIO SWDIO
SWCLK SWCLK
GND GND
3.3v 3.3v

Process

Launch the STM32CubeProgrammer Software.
Download the bootloader from here.
Select the correct connection method, in this instance its “stlink”. You may need to click the refesh button to find it. Then click connect.

STM32CubeProgrammer1
Connect via ST-Link

Then click on the “+” icon and find/open the bootloader file you downloaded earlier.

STM32CubeProgrammer2
Open File

Click the “Download” button.

STM32CubeProgrammer3
Download Bootloader to the board

A “File Download Complete” popup will appear once complete.

STM32CubeProgrammer4
Download Complete

Disconnect the board and continue flashing the firmware as normal.

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