diff --git a/.gitmodules b/.gitmodules
index d0ce0cb62f..9d14ad6da1 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -274,3 +274,6 @@
 [submodule "ports/stm/st_driver/CMSIS_5"]
 	path = ports/stm/st_driver/CMSIS_5
 	url = https://github.com/ARM-software/CMSIS_5.git
+[submodule "ports/stm/st_driver/stm32f4xx_hal_driver"]
+	path = ports/stm/st_driver/stm32f4xx_hal_driver
+	url = https://github.com/adafruit/stm32f4xx_hal_driver.git
diff --git a/ports/stm/st_driver/stm32f4xx_hal_driver b/ports/stm/st_driver/stm32f4xx_hal_driver
new file mode 160000
index 0000000000..abb4cd6a27
--- /dev/null
+++ b/ports/stm/st_driver/stm32f4xx_hal_driver
@@ -0,0 +1 @@
+Subproject commit abb4cd6a27ce4b95dd76d262a13d0e2c688b1f10