diff --git a/nrf5/modules/machine/modmachine.c b/nrf5/modules/machine/modmachine.c
index 276b248081..c847a4fc60 100644
--- a/nrf5/modules/machine/modmachine.c
+++ b/nrf5/modules/machine/modmachine.c
@@ -154,6 +154,7 @@ STATIC mp_obj_t machine_sleep(void) {
 MP_DEFINE_CONST_FUN_OBJ_0(machine_sleep_obj, machine_sleep);
 
 STATIC mp_obj_t machine_deepsleep(void) {
+    __WFI();
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_0(machine_deepsleep_obj, machine_deepsleep);