diff --git a/examples/FlashFull/FlashFull.ino b/examples/FlashFull/FlashFull.ino
index 6e446db..f47955f 100644
--- a/examples/FlashFull/FlashFull.ino
+++ b/examples/FlashFull/FlashFull.ino
@@ -94,4 +94,6 @@ static int sfud_demo(uint32_t addr, size_t size, uint8_t *data) {
         SERIAL.print(CostTime);
         SERIAL.println(" us");
     }
-}
\ No newline at end of file
+
+    return 0;
+}
diff --git a/src/Seeed_SFUD.cpp b/src/Seeed_SFUD.cpp
index ffc4521..4b43908 100644
--- a/src/Seeed_SFUD.cpp
+++ b/src/Seeed_SFUD.cpp
@@ -84,6 +84,8 @@ namespace fs
             free(flash_t);
             _pdrv = 0xFF;
         }
+
+        return true;
     }
     sfud_type_t SFUDFS::flashType()
     {
@@ -218,4 +220,4 @@ DRESULT flash_disk_ioctl(uint8_t pdrv, uint8_t cmd, void *buff)
     return RES_PARERR;
 }
 
-#endif
\ No newline at end of file
+#endif