diff --git a/components/esp32/cpu_start.c b/components/esp32/cpu_start.c
index fd46eec282..7b2ccdc609 100644
--- a/components/esp32/cpu_start.c
+++ b/components/esp32/cpu_start.c
@@ -55,7 +55,7 @@ static bool app_cpu_started = false;
 static void do_global_ctors(void);
 static void main_task(void* args);
 extern void ets_setup_syscalls(void);
-extern int app_main(void);
+extern void app_main(void);
 
 extern int _bss_start;
 extern int _bss_end;