diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index 6f02ba62c8..58390ba4c3 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -1160,52 +1160,54 @@ PX4IO::io_set_arming_state()
 	actuator_armed_s	armed;		///< system armed state
 	vehicle_control_mode_s	control_mode;	///< vehicle_control_mode
 
-	orb_copy(ORB_ID(actuator_armed), _t_actuator_armed, &armed);
-	orb_copy(ORB_ID(vehicle_control_mode), _t_vehicle_control_mode, &control_mode);
+	int have_armed = orb_copy(ORB_ID(actuator_armed), _t_actuator_armed, &armed);
+	int have_control_mode = orb_copy(ORB_ID(vehicle_control_mode), _t_vehicle_control_mode, &control_mode);
 
 	uint16_t set = 0;
 	uint16_t clear = 0;
 
-	if (armed.armed) {
-		set |= PX4IO_P_SETUP_ARMING_FMU_ARMED;
-
-	} else {
-		clear |= PX4IO_P_SETUP_ARMING_FMU_ARMED;
-	}
-
-	if (armed.lockdown && !_lockdown_override) {
-		set |= PX4IO_P_SETUP_ARMING_LOCKDOWN;
-	} else {
-		clear |= PX4IO_P_SETUP_ARMING_LOCKDOWN;
-	}
+        if (have_armed == OK) {
+		if (armed.armed) {
+			set |= PX4IO_P_SETUP_ARMING_FMU_ARMED;
+		} else {
+			clear |= PX4IO_P_SETUP_ARMING_FMU_ARMED;
+		}
 
-	/* Do not set failsafe if circuit breaker is enabled */
-	if (armed.force_failsafe && !_cb_flighttermination) {
-		set |= PX4IO_P_SETUP_ARMING_FORCE_FAILSAFE;
-	} else {
-		clear |= PX4IO_P_SETUP_ARMING_FORCE_FAILSAFE;
-	}
+		if (armed.lockdown && !_lockdown_override) {
+			set |= PX4IO_P_SETUP_ARMING_LOCKDOWN;
+		} else {
+			clear |= PX4IO_P_SETUP_ARMING_LOCKDOWN;
+		}
 
-	// XXX this is for future support in the commander
-	// but can be removed if unneeded
-	// if (armed.termination_failsafe) {
-	// 	set |= PX4IO_P_SETUP_ARMING_TERMINATION_FAILSAFE;
-	// } else {
-	// 	clear |= PX4IO_P_SETUP_ARMING_TERMINATION_FAILSAFE;
-	// }
+		/* Do not set failsafe if circuit breaker is enabled */
+		if (armed.force_failsafe && !_cb_flighttermination) {
+			set |= PX4IO_P_SETUP_ARMING_FORCE_FAILSAFE;
+		} else {
+			clear |= PX4IO_P_SETUP_ARMING_FORCE_FAILSAFE;
+		}
 
-	if (armed.ready_to_arm) {
-		set |= PX4IO_P_SETUP_ARMING_IO_ARM_OK;
+		// XXX this is for future support in the commander
+		// but can be removed if unneeded
+		// if (armed.termination_failsafe) {
+		// 	set |= PX4IO_P_SETUP_ARMING_TERMINATION_FAILSAFE;
+		// } else {
+		// 	clear |= PX4IO_P_SETUP_ARMING_TERMINATION_FAILSAFE;
+		// }
 
-	} else {
-		clear |= PX4IO_P_SETUP_ARMING_IO_ARM_OK;
+		if (armed.ready_to_arm) {
+			set |= PX4IO_P_SETUP_ARMING_IO_ARM_OK;
+			
+		} else {
+			clear |= PX4IO_P_SETUP_ARMING_IO_ARM_OK;
+		}
 	}
 
-	if (control_mode.flag_external_manual_override_ok) {
-		set |= PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK;
-
-	} else {
-		clear |= PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK;
+	if (have_control_mode == OK) {
+		if (control_mode.flag_external_manual_override_ok) {
+			set |= PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK;
+		} else {
+			clear |= PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK;
+		}
 	}
 
 	return io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, clear, set);
@@ -2198,7 +2200,7 @@ PX4IO::ioctl(file * filep, int cmd, unsigned long arg)
 		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
 		if (pwm->channel_count > _max_actuators)
 			/* fail with error */
-			return E2BIG;
+			return -E2BIG;
 
 		/* copy values to registers in IO */
 		ret = io_reg_set(PX4IO_PAGE_FAILSAFE_PWM, 0, pwm->values, pwm->channel_count);
@@ -2217,7 +2219,7 @@ PX4IO::ioctl(file * filep, int cmd, unsigned long arg)
 		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
 		if (pwm->channel_count > _max_actuators)
 			/* fail with error */
-			return E2BIG;
+			return -E2BIG;
 
 		/* copy values to registers in IO */
 		ret = io_reg_set(PX4IO_PAGE_DISARMED_PWM, 0, pwm->values, pwm->channel_count);
@@ -2236,7 +2238,7 @@ PX4IO::ioctl(file * filep, int cmd, unsigned long arg)
 		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
 		if (pwm->channel_count > _max_actuators)
 			/* fail with error */
-			return E2BIG;
+			return -E2BIG;
 
 		/* copy values to registers in IO */
 		ret = io_reg_set(PX4IO_PAGE_CONTROL_MIN_PWM, 0, pwm->values, pwm->channel_count);
@@ -2255,7 +2257,7 @@ PX4IO::ioctl(file * filep, int cmd, unsigned long arg)
 		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
 		if (pwm->channel_count > _max_actuators)
 			/* fail with error */
-			return E2BIG;
+			return -E2BIG;
 
 		/* copy values to registers in IO */
 		ret = io_reg_set(PX4IO_PAGE_CONTROL_MAX_PWM, 0, pwm->values, pwm->channel_count);
@@ -2592,9 +2594,9 @@ PX4IO::ioctl(file * filep, int cmd, unsigned long arg)
 		   on param_get() 
 		*/
 		struct pwm_output_rc_config* config = (struct pwm_output_rc_config*)arg;
-		if (config->channel >= _max_actuators) {
+		if (config->channel >= RC_INPUT_MAX_CHANNELS) {
 			/* fail with error */
-			return E2BIG;
+			return -E2BIG;
 		}
 
 		/* copy values to registers in IO */
diff --git a/src/modules/px4iofirmware/registers.c b/src/modules/px4iofirmware/registers.c
index a1a02965f4..f0c2cfd26d 100644
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@@ -412,7 +412,6 @@ registers_set(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num
 		 * text handling function.
 		 */
 		return mixer_handle_text(values, num_values * sizeof(*values));
-		break;
 
 	default:
 		/* avoid offset wrap */
@@ -584,10 +583,7 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 			break;
 
 		case PX4IO_P_SETUP_REBOOT_BL:
-			// do not reboot if FMU is armed and IO's safety is off
-			// this state defines an active system.
-			if ((r_status_flags & PX4IO_P_STATUS_FLAGS_SAFETY_OFF) &&
-			    (r_status_flags & PX4IO_P_SETUP_ARMING_FMU_ARMED)) {
+			if (r_status_flags & PX4IO_P_STATUS_FLAGS_SAFETY_OFF) {
 				// don't allow reboot while armed
 				break;
 			}
@@ -633,12 +629,9 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 	case PX4IO_PAGE_RC_CONFIG: {
 
 		/**
-		 * do not allow a RC config change while outputs armed
-		 * = FMU is armed and IO's safety is off
-		 * this state defines an active system.
+		 * do not allow a RC config change while safety is off
 		 */
-		if ((r_status_flags & PX4IO_P_STATUS_FLAGS_SAFETY_OFF) &&
-			    (r_status_flags & PX4IO_P_SETUP_ARMING_FMU_ARMED)) {
+		if (r_status_flags & PX4IO_P_STATUS_FLAGS_SAFETY_OFF) {
 			break;
 		}