diff --git a/rtl837x_common.h b/rtl837x_common.h
index 16380368..ee1c61bb 100644
--- a/rtl837x_common.h
+++ b/rtl837x_common.h
@@ -189,4 +189,5 @@ bool gpio_pin_test(uint8_t pin);
 void set_sys_led_state(uint8_t state);
 void sds_read(uint8_t sds_id, uint8_t page, uint8_t reg);
 void sds_write_v(uint8_t sds_id, uint8_t page, uint8_t reg, uint16_t v);
+void flash_default_config(void);
 #endif
diff --git a/rtlplayground.c b/rtlplayground.c
index b6b15b4b..0bb2f0aa 100644
--- a/rtlplayground.c
+++ b/rtlplayground.c
@@ -35,7 +35,6 @@ extern __xdata uint32_t flash_size;
 extern __xdata uint16_t crc_value;
 __xdata struct machine_runtime machine_detected;
 void crc16_bank1(__xdata uint8_t *v) __naked;
-void flash_default_config(void);
 
 // See setup_serial_timer1() for valid baudrate settings!
 #define SERIAL_BAUD_RATE 115200