14. Module2_Flashing The Blue Pill With A Cheap STLink Clone

Flashing The Blue Pill With A Cheap STLink Clone

• If you try to connect and try to flash a Blue Pill via an ST-Link clone (the ones widely available in grift marts online), you'll be forced into a firmware update that locks out devices with a specific internal ID which is unauthorised by ST.
• It seems as if we're out of luck. STM32CubeIDE is such an incredibly powerful tool, but if I can't get hold of a relatively expensive programmer, I can't program boards which are not officially distributed by STMicroelectronics.
• Thankfully, here's where the st-flash utility comes to our rescue.

What is st-flash?

• st-flash is a command-line utility for programming STM32 microcontrollers via the SWD interface using ST-Link programmers—both original and most clones.
• It is part of the stlink project on GitHub, and works on Windows, macOS, and Linux.

1. Prerequisites

• ST-Link V2 clone (can be found for a few dollars online)
• STM32 target board
• Wiring: Connect SWDIO, SWCLK, 3.3V, GND (optionally NRST) from the ST-Link to the STM32. Consult your board’s pinout.
• Binary or HEX firmware file to flash (e.g., my_firmware.bin)

2. Installation

Linux (Ubuntu/Debian)

sudo apt update  
sudo apt install stlink

macOS (with Homebrew)

brew install stlink

Windows

• Download prebuilt binaries or build from source:
  stlink GitHub Releases
• Add the binary folder to your PATH for convenient use.

3. Plug in Your ST-Link Clone

• Connect your ST-Link clone to the PC’s USB port.
• Plug in or connect your STM32 target as described above.

On Linux, you can check the device is detected by running:

lsusb

You should see an entry like STMicroelectronics ST-LINK/V2.

4. Basic Usage

Writing a Binary to Flash

st-flash write my_firmware.bin 0x08000000

• my_firmware.bin: your binary firmware file.
• 0x8000000: the starting FLASH address for STM32; this is typical for most STM32 MCUs.

Add --reset to automatically reset the MCU after flashing:

st-flash write my_firmware.bin 0x08000000 --reset

Reading Data from MCU

st-flash read output.bin 0x08000000 4096

This reads 4096 bytes starting from FLASH memory address 0x08000000 into output.bin.

5. Common Tips

• HEX files: You may flash .hex files directly; sometimes the address does not need to be specified since it’s included in the HEX.
• Permissions (Linux): You may need to run as root (sudo st-flash ...) or set up udev rules for non-root access.
• Erasing Flash: Flash is automatically erased prior to programming, but you can also mass-erase using:

st-flash erase

6. Advanced Options

• Specify target FLASH size for clones with larger memory:

st-flash --flash=128k write my_firmware.bin 0x08000000

(Use k or M suffix for kilobytes or megabytes).

7. Example of Common Commands**

Write firmware to board, then reset

st-flash write my_firmware.bin 0x8000000 --reset

Erase the entire flash

st-flash erase

Read out 4KB of flash from address 0x08000000

st-flash read dump.bin 0x08000000 4096

9. References and Further Reading

For a deep-dive, visit the [official stlink tutorial], [project repo], or practical connection how-to's.

Summary Table

Task	Command Example
Flash BIN	st-flash write my_firmware.bin 0x08000000 --reset
Read Flash	st-flash read dump.bin 0x08000000 4096
Erase Flash	st-flash erase
Set Flash Sz	st-flash --flash=128k write fw.bin 0x8000000

With these steps, you can reliably program STM32 microcontrollers using cheap ST-Link V2 clones with the st-flash utility on any platform.

Back to P5

---