diff --git a/ports/raspberrypi/supervisor/port.c b/ports/raspberrypi/supervisor/port.c
index 68d127704653..213084582b96 100644
--- a/ports/raspberrypi/supervisor/port.c
+++ b/ports/raspberrypi/supervisor/port.c
@@ -238,8 +238,8 @@ void port_interrupt_after_ticks(uint32_t ticks) {
 void port_idle_until_interrupt(void) {
     common_hal_mcu_disable_interrupts();
     if (!background_callback_pending()) {
-//	asm volatile ("dsb 0xF":::"memory");
-//        __wfi();
+        asm volatile ("dsb 0xF" ::: "memory");
+        __wfi();
     }
     common_hal_mcu_enable_interrupts();
 }