diff --git a/os/hal/ports/STM32/STM32F4xx/hal_efl_lld.h b/os/hal/ports/STM32/STM32F4xx/hal_efl_lld.h
index 9281d22bd..73eae8e66 100644
--- a/os/hal/ports/STM32/STM32F4xx/hal_efl_lld.h
+++ b/os/hal/ports/STM32/STM32F4xx/hal_efl_lld.h
@@ -81,7 +81,7 @@
  */
 #define STM32_FLASH_NUMBER_OF_BANKS         1
 #define STM32_FLASH1_SIZE                   128U
-#define STM32_FLASH2_SIZE                   512U
+#define STM32_FLASH2_SIZE                   256U
 #define STM32_FLASH3_SIZE                   384U
 #define STM32_FLASH4_SIZE                   512U
 #define STM32_FLASH1_SECTORS_TOTAL          5