diff --git a/cores/esp8266/StackThunk.cpp b/cores/esp8266/StackThunk.cpp
index 0d2a8a3541..d9cb0316fe 100644
--- a/cores/esp8266/StackThunk.cpp
+++ b/cores/esp8266/StackThunk.cpp
@@ -27,15 +27,20 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdio.h>
-#include "pgmspace.h"
+
 #include "debug.h"
 #include "StackThunk.h"
+
+#include <pgmspace.h>
 #include <ets_sys.h>
+
 #include <umm_malloc/umm_malloc.h>
 #include <umm_malloc/umm_heap_select.h>
 
 extern "C" {
 
+extern void optimistic_yield(uint32_t);
+
 uint32_t *stack_thunk_ptr = NULL;
 uint32_t *stack_thunk_top = NULL;
 uint32_t *stack_thunk_save = NULL;  /* Saved A1 while in BearSSL */
@@ -150,4 +155,9 @@ void stack_thunk_fatal_smashing()
     __stack_chk_fail();
 }
 
+void stack_thunk_yield()
+{
+    optimistic_yield(10000);
+}
+
 }
diff --git a/cores/esp8266/StackThunk.h b/cores/esp8266/StackThunk.h
index e72e0efb9f..350775ec24 100644
--- a/cores/esp8266/StackThunk.h
+++ b/cores/esp8266/StackThunk.h
@@ -31,6 +31,8 @@
 extern "C" {
 #endif
 
+extern void stack_thunk_yield(void);
+
 extern void stack_thunk_add_ref();
 extern void stack_thunk_del_ref();
 extern void stack_thunk_repaint();