diff --git a/libraries/GCS_MAVLink/GCS_Common.cpp b/libraries/GCS_MAVLink/GCS_Common.cpp
index baca8fc588..7cd9661839 100644
--- a/libraries/GCS_MAVLink/GCS_Common.cpp
+++ b/libraries/GCS_MAVLink/GCS_Common.cpp
@@ -2551,8 +2551,13 @@ MAV_RESULT GCS_MAVLINK::handle_preflight_reboot(const mavlink_command_long_t &pa
     // flush pending parameter writes
     AP_Param::flush();
 
+    // do not process incoming mavlink messages while we delay:
+    hal.scheduler->register_delay_callback(nullptr, 5);
+
+    // delay to give the ACK a chance to get out, the LEDs to flash,
+    // the IO board safety to be forced on, the parameters to flush, ...
     hal.scheduler->delay(200);
-    
+
     // when packet.param1 == 3 we reboot to hold in bootloader
     const bool hold_in_bootloader = is_equal(packet.param1, 3.0f);
     hal.scheduler->reboot(hold_in_bootloader);