diff --git a/platformio.ini b/platformio.ini
index d8f77ea..fa9e452 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -2,6 +2,7 @@
 platform = espressif8266
 board = esp12e
 framework = arduino
+build_flags = -D PIO_FRAMEWORK_ARDUINO_ESPRESSIF_SDK305
 board_build.filesystem = littlefs
 board_build.ldscript = eagle.flash.4m1m.ld
 lib_deps = 
@@ -14,6 +15,7 @@ lib_deps =
 platform = espressif8266
 board = esp12e
 framework = arduino
+build_flags = -D PIO_FRAMEWORK_ARDUINO_ESPRESSIF_SDK305
 board_build.filesystem = littlefs
 board_build.ldscript = eagle.flash.4m1m.ld
 upload_port = 192.168.4.1