diff --git a/platformio.ini b/platformio.ini
index 82ebd17..5532f7c 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -16,3 +16,4 @@ build_flags =
     -Os
     -Wl,--defsym,_Min_Heap_Size=0x2000
     -Wl,--defsym,_Min_Stack_Size=0x1000
+    -Wl,--defsym,__stack_end=_estack-0x1000