Flashing STM32 From CM4

In order to use the Raspberry Pi CM4 to upload firmware to the STM32, we need a custom version of OpenOCD which can use the CM4’s GPIOs to connect to the STM32’s SWD interface.

Step 1: Building OpenOCD

Execute the following commands in order to install the dependencies, build and install OpenOCD:

sudo apt install automake autoconf build-essential libtool libftdi-dev libusb-1.0-0-dev texinfo pkg-config rpi.gpio-common curl
git clone https://github.com/raspberrypi/openocd.git --recursive
cd openocd
./bootstrap
./configure --enable-ftdi --enable-sysfsgpio --enable-bcm2835gpio
make -j$(nproc)
sudo make install

Step 2: Get the OpenOCD Configuration

Fetch the configuration and install it globally for OpenOCD to find it:

sudo curl -o /usr/local/share/openocd/scripts/interface/xcore.cfg https://core.x-tech.online/downloads/openocd-xcore.cfg

Step 3: Upload a binary

Get a binary (.elf format) and upload it to the STM32 like this:

openocd -f interface/xcore.cfg -f target/stm32h7x.cfg -c "program your-binary.elf verify reset exit"

The firmware should be uploaded and the program should be running.