diff --git a/cores/esp8266/flash_utils.h b/cores/esp8266/flash_utils.h
index 67dc6ebadd..66730b4b5b 100644
--- a/cores/esp8266/flash_utils.h
+++ b/cores/esp8266/flash_utils.h
@@ -21,6 +21,9 @@
 #ifndef FLASH_UTILS_H
 #define FLASH_UTILS_H
 
+#include "c_types.h"
+#include "spi_flash.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -31,7 +34,7 @@ int SPIRead(uint32_t addr, void *dest, size_t size);
 int SPIWrite(uint32_t addr, void *src, size_t size);
 int SPIEraseAreaEx(const uint32_t start, const uint32_t size);
 
-#define FLASH_SECTOR_SIZE 0x1000
+#define FLASH_SECTOR_SIZE SPI_FLASH_SEC_SIZE
 #define FLASH_BLOCK_SIZE 0x10000
 #define APP_START_OFFSET 0x1000