diff --git a/libraries/AP_HAL_ChibiOS/hwdef/f405-bl/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/f405-bl/hwdef.dat
new file mode 100644
index 0000000000..51fcffe272
--- /dev/null
+++ b/libraries/AP_HAL_ChibiOS/hwdef/f405-bl/hwdef.dat
@@ -0,0 +1,39 @@
+# hw definition file for processing by chibios_pins.py
+# for minimal F405 bootloader
+
+# MCU class and specific type
+MCU STM32F4xx STM32F405xx
+
+# board ID for firmware load
+APJ_BOARD_ID 3
+
+# crystal frequency
+OSCILLATOR_HZ 8000000
+STM32_PLLM_VALUE 8
+
+FLASH_SIZE_KB 1024
+
+USB_STRING_PRODUCT "f745-BL"
+
+# bootloader is installed at zero offset
+FLASH_RESERVE_START_KB 0
+
+# LEDs
+PB9 LED_BOOTLOADER OUTPUT LOW GPIO(0)
+PA14 LED_ACTIVITY  OUTPUT LOW GPIO(1)
+define HAL_LED_ON 0
+
+# the location where the bootloader will put the firmware
+define FLASH_BOOTLOADER_LOAD_KB 64
+
+# board voltage
+STM32_VDD 330U
+
+# order of UARTs
+UART_ORDER OTG1
+
+PA11 OTG_FS_DM OTG1
+PA12 OTG_FS_DP OTG1
+
+define HAL_USE_EMPTY_STORAGE 1
+define HAL_STORAGE_SIZE 16384