diff --git a/src/modules/px4iofirmware/mixer.cpp b/src/modules/px4iofirmware/mixer.cpp
index 66f0969de1..835dfc0f5e 100644
--- a/src/modules/px4iofirmware/mixer.cpp
+++ b/src/modules/px4iofirmware/mixer.cpp
@@ -272,8 +272,9 @@ mixer_tick(void)
 
 	if (mixer_servos_armed && should_arm) {
 		/* update the servo outputs. */
-		for (unsigned i = 0; i < PX4IO_SERVO_COUNT; i++)
+		for (unsigned i = 0; i < PX4IO_SERVO_HARDWARE_COUNT; i++) {
 			up_pwm_servo_set(i, r_page_servos[i]);
+		}
 
 		/* set S.BUS1 or S.BUS2 outputs */
 
@@ -285,8 +286,9 @@ mixer_tick(void)
 
 	} else if (mixer_servos_armed && should_always_enable_pwm) {
 		/* set the disarmed servo outputs. */
-		for (unsigned i = 0; i < PX4IO_SERVO_COUNT; i++)
+		for (unsigned i = 0; i < PX4IO_SERVO_HARDWARE_COUNT; i++) {
 			up_pwm_servo_set(i, r_page_servo_disarmed[i]);
+		}
 
 		/* set S.BUS1 or S.BUS2 outputs */
 		if (r_setup_features & PX4IO_P_SETUP_FEATURES_SBUS1_OUT)
diff --git a/src/modules/px4iofirmware/px4io.h b/src/modules/px4iofirmware/px4io.h
index 93a33490fa..df2633cc5a 100644
--- a/src/modules/px4iofirmware/px4io.h
+++ b/src/modules/px4iofirmware/px4io.h
@@ -51,7 +51,8 @@
 /*
  * Constants and limits.
  */
-#define PX4IO_SERVO_COUNT		8
+#define PX4IO_SERVO_COUNT		16
+#define PX4IO_SERVO_HARDWARE_COUNT	8
 #define PX4IO_CONTROL_CHANNELS		8
 #define PX4IO_CONTROL_GROUPS		4
 #define PX4IO_RC_INPUT_CHANNELS		18