bootloader

A bootloader for STM32F030 with encryption + PC-tools. The bootloader works via UART. A firmware is encrypted with AES-128 and is protected against communication errors with CRC-32.

Content

• bl_f030 - the bootloader itself
• creator - PC tool to create an encrypted file with firmware
• control - PC tool to download the encrypted firmware into uC
• led_example - a very simple example firmware
• echo_example - a bit more real firmware

The PC-tools are developed with Qt and may be compiled for Windows (untested) or Linux (tested).

How to use

You as developer, one time

Make a copy of bl_f030, take a look into main.c. Here you should change the define PRODUCT_ID to something unique for each your project - just to avoid a user mistakes. In any case you must change the KEY to random 16 bytes.

You might want to change the condition to start the bootloader too. Default - wait 1 second for command from the 'control'. Check any other hardware-specific options. The bootloader is configured for UART 115200 8N1, TX on PA9, RX on PA10.

Now compile and flash the bootloader. Don't forget to set the read protection (see RM0360, chapter 3.3.1).

You as developer, each upgrade

Your app must start from 0x08001000 and leave first 192 bytes of RAM unused. E.g. see echo_example/ld/mem.ld.

After compiling your firmware, use 'creator' to encrypt it. Enter 'Product ID' and 'Key' exactly as in your copy of bl_f030. 'App Version' - anything, just to help your users to distinct upgrades.

Your user

Provide 'control' together with the encrypted firmware.

The user has to:

1. Connect a device via UART (e.g. using UART-USB adapter).
2. Start the 'control'.
3. Select corresponding UART interface and 'Connect'.
4. Restart the device.
5. Now the 'control' should connect to the device and show its Product-ID and protocol version.
6. Select the encrypted firmware in 'Input file'. If the device matches the firmware, The 'Download' button will be enabled.
7. Click 'Download' and wait for success message (a few seconds).
8. 'Disconnect' - the device is upgraded.