diff --git a/port/fal/samples/porting/fal_flash_stm32f2_port.c b/port/fal/samples/porting/fal_flash_stm32f2_port.c
index 81c8ca3..35bb8f2 100644
--- a/port/fal/samples/porting/fal_flash_stm32f2_port.c
+++ b/port/fal/samples/porting/fal_flash_stm32f2_port.c
@@ -146,6 +146,7 @@ static int write(long offset, const uint8_t *buf, size_t size)
         /* check data */
         if (read_data != *buf)
         {
+            FLASH_Lock();
             return -1;
         }
     }
@@ -173,6 +174,7 @@ static int erase(long offset, size_t size)
         flash_status = FLASH_EraseSector(cur_erase_sector, VoltageRange_3);
         if (flash_status != FLASH_COMPLETE)
         {
+            FLASH_Lock();
             return -1;
         }
         erased_size += stm32_get_sector_size(cur_erase_sector);
diff --git a/port/fal/samples/porting/fal_flash_stm32f4.c b/port/fal/samples/porting/fal_flash_stm32f4.c
index 1cb124b..8505fb3 100644
--- a/port/fal/samples/porting/fal_flash_stm32f4.c
+++ b/port/fal/samples/porting/fal_flash_stm32f4.c
@@ -182,11 +182,13 @@ static int write(long offset, const uint8_t *buf, size_t size)
         {
             if (*(uint8_t *) addr != *buf)
             {
+                HAL_FLASH_Lock();
                 return -1;
             }
         }
         else
         {
+            HAL_FLASH_Lock();
             return -1;
         }
     }
@@ -221,6 +223,7 @@ static int erase(long offset, size_t size)
 
     if (HAL_FLASHEx_Erase(&EraseInitStruct, (uint32_t *) &SECTORError) != HAL_OK)
     {
+        HAL_FLASH_Lock();
         return -1;
     }