STM32L4 Bootloader Simulation

A simple educational STM32L4 bootloader written in C, demonstrating firmware loading, CRC verification, and flash memory management. Includes a simulated flash interface and detailed logging for each step.

Features

• Simulated flash memory with read, write, and erase operations
• CRC32 checksum verification of loaded firmware
• Loads firmware from a binary file (app.bin)
• Step-by-step logging of bootloader operations
• Modular C code suitable for learning embedded bootloader concepts

Project Structure

stm32-bootloader/
├── inc/                # Header files
│   ├── bootloader.h
│   ├── crc32.h
│   └── flash.h
├── src/                # Source files
│   ├── main.c
│   ├── bootloader.c
│   ├── crc32.c
│   └── flash.c
├── tools/              # Helper scripts
│   └── mkapp.py        # Generates app.bin firmware
├── app.bin             # Example firmware
├── Makefile
└── README.md

Usage

1. Build the bootloader simulator

make

2. Run the simulator

./bootloader_sim

The simulator will:

• Erase the simulated flash
• Load app.bin into flash memory
• Verify CRC checksum
• “Jump” to the application

Adding Your Firmware

Use the provided Python tool tools/mkapp.py to generate a new firmware binary (app.bin) for testing.

python tools/mkapp.py

Project Status / Next Steps

• Current: Fully functional simulated bootloader
• Next: Integrate with actual STM32 hardware for real flash programming
• Future: Add UART / USB DFU update support, multiple applications, advanced CRC algorithms

License

MIT License © 2025 Amen Ellah Kerimi
https://amenellah.kerimi.com