diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
index c71cad6aeb..009b428645 100644
--- a/py/circuitpy_mpconfig.h
+++ b/py/circuitpy_mpconfig.h
@@ -96,6 +96,7 @@
 #define MICROPY_PY_BUILTINS_SET          (1)
 #define MICROPY_PY_BUILTINS_SLICE        (1)
 #define MICROPY_PY_BUILTINS_SLICE_ATTRS  (1)
+#define MICROPY_PY_BUILTINS_SLICE_INDICES (1)
 #define MICROPY_PY_BUILTINS_STR_UNICODE  (1)
 
 #define MICROPY_PY_CMATH                 (0)