diff --git a/ArduPlane/system.pde b/ArduPlane/system.pde
index d994ff9bc0..0a6c1ec7b5 100644
--- a/ArduPlane/system.pde
+++ b/ArduPlane/system.pde
@@ -109,9 +109,6 @@ static void init_ardupilot()
 
     // init the GCS
     gcs[0].init(hal.uartA);
-    // Register mavlink_delay_cb, which will run anytime you have
-    // more than 5ms remaining in your call to hal.scheduler->delay
-    hal.scheduler->register_delay_callback(mavlink_delay_cb, 5);
 
     // we start by assuming USB connected, as we initialed the serial
     // port with SERIAL0_BAUD. check_usb_mux() fixes this if need be.    
@@ -150,6 +147,10 @@ static void init_ardupilot()
     }
 #endif
 
+    // Register mavlink_delay_cb, which will run anytime you have
+    // more than 5ms remaining in your call to hal.scheduler->delay
+    hal.scheduler->register_delay_callback(mavlink_delay_cb, 5);
+
 #if CONFIG_INS_TYPE == CONFIG_INS_OILPAN || CONFIG_HAL_BOARD == HAL_BOARD_APM1
     apm1_adc.Init();      // APM ADC library initialization
 #endif