How to use Zadig: How to install STM32 BOOTLOADER

To access the firmware of FPV drones and OpenTX/EdgeTX radios using STM32 processors on Windows PC, it is necessary to install a driver called "STM32 BOOTLOADER". Normally this driver is not installed automatically and must be installed manually. Here, we will introduce how to install STM32 BOOTLOADER on a Windows computer using free software called "Zadig".

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Check driver

With the power off, connect the OpenTX/EdgeTX radio to your computer using a USB cable. Then wait for a while for Windows to recognize the device. Then open Windows Device Manager.
If you see "STM32 BOOTLOADER" in the "Other devices" column like this, the driver has not been installed correctly. Follow the steps below to install the driver.

How to open Windows Device Manager
Open [Start]-[All apps]-[Windous Tools(Win11) / Windows management tools (Win10)] and double-click "Computer Management". Then click "Device Manager" from the left menu.
Or open [Start]-[Windows System Tools]-[Control Panel] and select [System and Security]-[System]-[Device Manager].

Use a USB cable "For data communication"
There are two types of USB cables: "For data communication" where all terminals are connected, and "For charging" where only power supply terminals are connected. You need to use "For data communication" to communicate with OpenTX/EdgeTX Companion. Please note that some cables attached to bonus of mobile phone or charger, battery are "For charging".

Install the driver : STM32 BOOTLOADER

Use free software called "Zadig" to install the driver. Open Zadig official site (https://zadig.akeo.ie/) , and download latest Zadig from "Download" column. Then you can download a file with a name like “zadig-2.5.exe”, so double-click it to start.

Then you will see a screen like this. This is a confirmation screen as to whether or not to check upgrade of "Zadig" itself. Please select as you like.

And you will see a screen like this. "STM32 BOOTLOADER" is selected as the driver to install. If "STM32 BOOTLOADER" is not selected, select [Options]-[List All Devices] from menu, and then select "STM32 BOOTLOADER" from drop-down list. Then click "Install Driver" button.

Are the text boxes blank?
If you have never connected a radio to your computer before, you may find that on this screen all the text boxes are blank and you cannot select anything. First, connect computer and radio with the power turned off with a USB cable, wait for a while, and then start Zadig.