- Small size. Fits in 4K ROM segment (ASM or no encryption, otherwise a bit more).
- USB DFU1.1 compatible
- Supported by dfu-util
- Supported ciphers:
- No encryption
- ARCFOUR stream cipher
- CHACHA20 stream cipher
- RC5-32/12/16 block cipher (C and ASM implementation)
- RC6-32/20/16 block cipher (C and ASM implementation)
- GOST R 34.12-2015 "MAGMA" block cipher
- RAIDEN block cipher
- SPECK 64/128 block cipher
- XTEA (classic and XTEA-1) block cipher
- RTEA block cipher
- BLOWFISH type block cipher
- Rijndael AES-128/192/256 block cipher
- Supported cipher modes for block ciphers:
- Electronic Codebook (ECB)
- Cipher Block Chaining (CBC)
- Propagating CBC (PCBC)
- Cipher Feedback (CFB)
- Output Feedback (OFB)
- Counter (CTR)
- Supported firmware verification methods:
- CRC (CRC32, CRC64)
- Fowler-Noll-Vo (FNV-1A-32, FNV1A-64)
- Separate interfaces for flash and EEPROM programming
- Autoseal using RDP level 1 or 2 (prevents reading decrypted FW trough debug interface). Be careful when you set RDP to level 2. This operation is irreversible and disables all debug functions and option bytes programming.
- Software for firmware encryption/decryption included
- Supported STM32 families:
- STM32L0x2
- STM32L1xx
- STM32L476xx (OTG FS in device mode)
- STM32F103
- STM32F105, STM32F107 (OTG FS in device mode)
- STM32F0 series
- STM32F3 series
- STM32F4 series
- STM32G4 series
The bootloader can be configured through the make parameters. See CONFIG.md for details.
- Prerequisites
- GNU make
- arm-none-eabi-gcc toolchaipren v4.9 or later to build bootloader
- gcc toolchain to build fwcrypt software
- CMSIS V4 or CMSIS V5.
- Device peripheral access layer header files for STM32. See Vendor Template for details.
- stm32.h STM32 universal header
- optional st-util tool to program bootloader
- Makefile targets
- make prerequisites to download required libs and headers
- make mcu_target to build bootloader
- make program to flash bootloader using st-flash
- make crypter to build encryption software
- Makefile and environmental variables
| Variable | Default Value | Description |
|---|---|---|
| CMSIS | CMSIS | path to CMSIS root folder |
| CMSISDEV | $(CMSIS)/Device | path to CMSIS device folder |
| OUTDIR | build | output folder for binaries |
| FWNAME | firmware | name for bootloader binary |
| SWNAME | fwcrypt | name for encrypter binary |
- MCU targets
| mcu_target | MCU | remarks |
|---|---|---|
| stm32l100x6a | STM32L100C6-A | |
| stm32l100x8a | STM32L100R8-A | |
| stm32l100xba | STM32L100RB-A | |
| stm32l100xc | STM32L100RC | tested |
| stm32l151x6a | STM32L151C6-A, STM32L151R6-A | |
| stm32l151x8a | STM32L151C8-A, STM32L151R8-A, STM31L151V8-A | |
| stm32l151xba | STM32L151CB-A, STM32L151RB-A, STM31L151VB-A | |
| stm32l151xc | STM32L151CC, STM32L151QC, SRM32L151RC, STM32L151UC | |
| stm32l151xd | STM32L151QD, STM32L151RD, STM32L151VD, STM32L151ZD | |
| stm32l151xe | STM32L151QE, STM32L151RE, STM32L151VE, STM32L151ZE | |
| stm32l152x6a | STM32L152C6-A, STM32L152R6-A | |
| stm32l152x8a | STM32L152C8-A, STM32L152R8-A, STM31L152V8-A | |
| stm32l152xba | STM32L152CB-A, STM32L152RB-A, STM31L152VB-A | |
| stm32l152xc | STM32L152CC, STM32L152QC, SRM32L152RC, STM32L152UC | |
| stm32l152xd | STM32L152QD, STM32L152RD, STM32L152VD, STM32L152ZD | |
| stm32l152xe | STM32L152QE, STM32L152RE, STM32L152VE, STM32L152ZE | |
| stm32l162xc | STM32L162RC, STM32L162VC | |
| stm32l162xd | STM32L162QD, STM32L156RD, STM32L162VD, STM32L162ZD | |
| stm32l162xe | STM32L162QE, STM32L156RE, STM32L162VE, STM32L162ZE | |
| stm32l052x6 | STM32L052K6, STM32L052T6, STM32L052C6, STM32L052R6 | |
| stm32l052x8 | STM32L052K8, STM32L052T8, STM32L052C8, STM32L052R8 | tested, default |
| stm32l053x6 | STM32L053C6, STM32L053R6 | |
| stm32l053x8 | STM32L053C8, STM32L053R8 | |
| stm32l062x8 | STM32L062K8 | |
| stm32l063x8 | STM32L063C8, STM32L063R8 | |
| stm32l072v8 | STM32L072V8 | |
| stm32l072xb | STM32L072KB, STM32L072CB, STM32L072RB, STM32L072VB | tested |
| stm32l072xz | STM32L072KZ, STM32L072CZ, STM32L072RZ, STM32L072VZ | |
| stm32l073v8 | STM32L073V8 | |
| stm32l073xb | STM32L073CB, STM32L073RB, STM32L073VB | |
| stm32l073xz | STM32L073CZ, STM32L073RZ, STM32L073VZ | |
| stm32l476xc | STM32L476RC, STM32L476VC | |
| stm32l476xe | STM32L476RE, STM32L476JE, STM32L476ME, STM32L476VE | |
| stm32l476xg | STM32L476RG, STM32L476JG, STM32L476MG, STM32L476VG | tested |
| stm32f103x6 | STM32F103T6, STM32F103C6, STM32F103R6 | |
| stm32f103x8 | STM32F103T8, STM32F103C8, STM32F103R8, STM32f103V8 | tested |
| stm32f105xb | STM32F105RB, STM32F105VB | tested |
| stm32f107xb | STM32F107RB, STM32F107VB | tested |
| stm32l433xb | STM32L433CB, STM32L433RB | |
| stm32l433xc | STM32L433CC, STM32L433RC, STM32L433VC | tested |
| stm32f070x6 | STM32F070C6 | |
| stm32f070xb | STM32F070CB | tested |
| stm32f429xe | STM32F429xE series (single bank mode) | |
| stm32f429xg | STM32F429xG series (single bank mode) | |
| stm32f429xi | STM32F429xI series (single and dual bank) | tested |
| stm32g431x6 | STM32G431x6, STM32G441x6 | |
| stm32g431x8 | STM32G431x8, STM32G441x8 | |
| stm32g431xb | STM32G431xB, STM32G441xB | tested G431RB |
| stm32g474xb | STM32G471xB, STM32G473xB, STM32G474xB, STM32G483xB | |
| stm32g474xc | STM32G471xC, STM32G473xC, STM32G474xC, STM32G483xC | |
| stm32g474xe | STM32G471xE, STM32G473xE, STM32G474xE, STM32G483xE | tested G747RE |
| stm32f303xe | STM32F303xE | tested |
| stm32f373xc | STM32F373xC | tested |
- Check bootloader's linker map for the
__app_startaddress. This is the new ROM origin for the user firmware (ISR vectors). - Adjust your linker script to set new ROM origin and ROM length.
- Check bootloader's linker map for the
usbd_pollentry point and usbd driver (usbd_devfs,usbd_otgfs, e.t.c. depends used MCU). It's located just after the.isr_vectorsection. - Add address for usbd_driver structure to your linker script. For example
usbd_drv = 0x08000040; - Add address for usbd_poll entry point to your linker script. For example
usbd_poll = 0x08000074; - Add
extern struct usbd_driver usbd_drv;driver declaration to your code. - Include at least "usbd_core.h" and "usb_std.h" to your code.
Now you can use the usbd core and driver from the bootloader in your application. Don't forget to set GPIO and RCC for USB according to MCU requirements.
- Write DFU_BOOTKEY at DFU_BOOTKEY_ADDR (RAM top by default) and make a software reset.
- Assert DFU_BOOTSTRAP_PIN on DFU_BOOTSTRAP_PORT on startup (optional).
- Make a double reset during the DFU_DBLRESET_MS period (optional).
We provide a utility for encryption and decryption of firmware images. At this moment, only raw binary files are supported.
To encrypt:
fwcrypt -e -i infile.bin -o outfile.bin
To decrypt:
fwcrypt -d -i infile.bin -o outfile.bin