diff --git a/esp8266/mpconfigport.h b/esp8266/mpconfigport.h
index 153d096f10a09aa69c49e88a917359aaecd8ab97..e2c7f57e22e5f1249c4343464a0614122ff47f92 100644
--- a/esp8266/mpconfigport.h
+++ b/esp8266/mpconfigport.h
@@ -152,6 +152,6 @@ extern const struct _mp_obj_module_t onewire_module;
 #define MICROPY_MPHALPORT_H "esp_mphal.h"
 #define MICROPY_HW_BOARD_NAME "ESP module"
 #define MICROPY_HW_MCU_NAME "ESP8266"
-#define MICROPY_PY_SYS_PLATFORM "ESP8266"
+#define MICROPY_PY_SYS_PLATFORM "esp8266"
 
 #define _assert(expr) ((expr) ? (void)0 : __assert_func(__FILE__, __LINE__, __func__, #expr))