HWFail if GPS functionality is removed later

[Target0815]

Current Behavior

Fresh installation of INAV 9.01 on Radiomaster NEXUS-XR, airframe without tail (wing), GPS on UART 6. One switch assigned to MANUAL, ANGLE, and NAV RTH. Everything else is set to default. Works without any issues.

Now I want to fly the wing without GPS (removed). However, the above configuration does not allow this. Arm is rejected with an HWFail. @b14ckyy said at FB this is because NAV Modes are defined or RTH is triggered by Failsafe.

But even after removing the NAV Modes and setting Failsafe to "Do nothing," an HWFail still occurs and the speed icon lights up red.

Expected behavior

If the GPS is removed or the GPS functions are disabled, the configuration should behave as if GPS had not been selected or enabled during the initial setup.

[b14ckyy]

please post a DIFF from your config with disabled GPS (as a TXT or code block, not just paste) in the config where you would not expect a HW Failure with disabled GPS.

[sensei-hacker]

But even after removing the NAV Modes and setting Failsafe to "Do nothing," an HWFail still occurs and the speed icon lights up red.

Did you turn off "GPS Navigation"?

[Target0815]

Airplane with Tail and without GPS:

Entering CLI Mode, type 'exit' to return, or 'help'

# diff

# version
# INAV/NEXUSX 9.0.1 Feb 13 2026 / 06:53:16 (d44f2cf6) 
# GCC-13.2.1 20231009

# start the command batch
batch start

# resources

# Timer overrides

# Outputs [servo]

# safehome

# Fixed Wing Approach

# features
feature PWM_OUTPUT_ENABLE

# beeper

# blackbox
blackbox -NAV_ACC
blackbox NAV_POS
blackbox NAV_PID
blackbox MAG
blackbox ACC
blackbox ATTI
blackbox RC_DATA
blackbox RC_COMMAND
blackbox MOTORS
blackbox -GYRO_RAW
blackbox -PEAKS_R
blackbox -PEAKS_P
blackbox -PEAKS_Y
blackbox SERVOS

# Receiver: Channel map
map TAER

# Ports

# Modes [aux]
aux 0 0 0 1700 2100
aux 1 1 3 1300 1700
aux 2 12 3 900 1300

# Adjustments [adjrange]

# Receiver rxrange

# temp_sensor

# Mission Control Waypoints [wp]
#wp 0 invalid

# OSD [osd_layout]

# Programming: logic

# Programming: global variables

# Programming: PID controllers

# OSD: custom elements

# master
set looptime = 1000
set gyro_main_lpf_hz = 25
set dynamic_gyro_notch_q = 250
set dynamic_gyro_notch_min_hz = 30
set gyro_zero_x = 1
set gyro_zero_y = 1
set ins_gravity_cmss =  983.008
set gyro_adaptive_filter_min_hz = 20
set acc_hardware = ICM42605
set acczero_x = 1
set acczero_y = -1
set acczero_z = 1
set accgain_x = 4100
set accgain_y = 4090
set accgain_z = 4091
set align_mag = CW270FLIP
set mag_hardware = NONE
set baro_hardware = SPL06
set blackbox_rate_denom = 2
set motor_pwm_protocol = STANDARD
set small_angle = 180
set applied_defaults = 3
set airmode_type = STICK_CENTER_ONCE
set nav_wp_radius = 800
set nav_wp_max_safe_distance = 500
set nav_rth_allow_landing = FS_ONLY
set nav_rth_altitude = 5000
set nav_fw_control_smoothness = 2
set nav_fw_launch_motor_delay = 100
set nav_fw_launch_max_altitude = 5000
set nav_fw_launch_climb_angle = 25

# control_profile
control_profile 1

set fw_p_pitch = 15
set fw_i_pitch = 5
set fw_d_pitch = 5
set fw_ff_pitch = 80
set fw_p_roll = 15
set fw_i_roll = 3
set fw_d_roll = 7
set fw_p_yaw = 50
set fw_i_yaw = 0
set fw_d_yaw = 20
set fw_ff_yaw = 255
set dterm_lpf_hz = 10
set fw_turn_assist_pitch_gain =  0.400
set nav_fw_pos_z_p = 22
set nav_fw_pos_z_i = 6
set nav_fw_pos_z_d = 2
set nav_fw_alt_control_response = 45
set nav_fw_pos_xy_p = 55
set d_boost_min =  1.000
set d_boost_max =  1.000
set tpa_rate = 80
set rc_expo = 30
set rc_yaw_expo = 30
set roll_rate = 18
set pitch_rate = 9
set yaw_rate = 3

# mixer_profile
mixer_profile 1

set platform_type = AIRPLANE
set has_flaps = ON
set model_preview_type = 14

# Mixer: motor mixer

mmix reset

mmix 0  1.000  0.000  0.000  0.000

# Mixer: servo mixer
smix reset

smix 0 1 1 100 0 -1
smix 1 2 0 100 0 -1
smix 2 3 0 100 0 -1
smix 3 4 2 100 0 -1

# battery_profile
battery_profile 1

set throttle_idle =  5.000

# save configuration
save

# end the command batch
batch end

# 

I think I've found the problem... In this configuration, GPS wasn't selected or enabled. Yet "HWFail" is still displayed. This is due to the default configuration: Pitot Tube = VIRTUAL. If I set it to "None," the error disappears.

Airplane with tail and with GPS:

Entering CLI Mode, type 'exit' to return, or 'help'

# diff

# version
# INAV/NEXUSX 9.0.1 Feb 13 2026 / 06:53:16 (d44f2cf6) 
# GCC-13.2.1 20231009

# start the command batch
batch start

# resources

# Timer overrides

# Outputs [servo]

# safehome

# Fixed Wing Approach

# features
feature GPS
feature PWM_OUTPUT_ENABLE

# beeper

# blackbox
blackbox -NAV_ACC
blackbox NAV_POS
blackbox NAV_PID
blackbox MAG
blackbox ACC
blackbox ATTI
blackbox RC_DATA
blackbox RC_COMMAND
blackbox MOTORS
blackbox -GYRO_RAW
blackbox -PEAKS_R
blackbox -PEAKS_P
blackbox -PEAKS_Y
blackbox SERVOS

# Receiver: Channel map
map TAER

# Ports
serial 5 2 115200 115200 0 115200

# Modes [aux]
aux 0 0 0 1700 2100
aux 1 1 3 1300 1700
aux 2 12 3 900 1300

# Adjustments [adjrange]

# Receiver rxrange

# temp_sensor

# Mission Control Waypoints [wp]
#wp 0 invalid

# OSD [osd_layout]

# Programming: logic

# Programming: global variables

# Programming: PID controllers

# OSD: custom elements

# master
set looptime = 1000
set gyro_main_lpf_hz = 25
set dynamic_gyro_notch_q = 250
set dynamic_gyro_notch_min_hz = 30
set gyro_zero_x = 1
set gyro_zero_y = 1
set ins_gravity_cmss =  979.381
set gyro_adaptive_filter_min_hz = 20
set acc_hardware = ICM42605
set acczero_x = 1
set acczero_y = -1
set accgain_x = 4083
set accgain_y = 4090
set accgain_z = 4075
set align_mag = CW270FLIP
set mag_hardware = NONE
set baro_hardware = SPL06
set pitot_hardware = VIRTUAL
set blackbox_rate_denom = 2
set motor_pwm_protocol = STANDARD
set small_angle = 180
set applied_defaults = 3
set airmode_type = STICK_CENTER_ONCE
set nav_wp_radius = 800
set nav_wp_max_safe_distance = 500
set nav_rth_allow_landing = FS_ONLY
set nav_rth_altitude = 5000
set nav_fw_control_smoothness = 2
set nav_fw_launch_motor_delay = 100
set nav_fw_launch_max_altitude = 5000
set nav_fw_launch_climb_angle = 25

# control_profile
control_profile 1

set fw_p_pitch = 15
set fw_i_pitch = 5
set fw_d_pitch = 5
set fw_ff_pitch = 80
set fw_p_roll = 15
set fw_i_roll = 3
set fw_d_roll = 7
set fw_p_yaw = 50
set fw_i_yaw = 0
set fw_d_yaw = 20
set fw_ff_yaw = 255
set dterm_lpf_hz = 10
set fw_turn_assist_pitch_gain =  0.400
set nav_fw_pos_z_p = 22
set nav_fw_pos_z_i = 6
set nav_fw_pos_z_d = 2
set nav_fw_alt_control_response = 45
set nav_fw_pos_xy_p = 55
set d_boost_min =  1.000
set d_boost_max =  1.000
set tpa_rate = 80
set rc_expo = 30
set rc_yaw_expo = 30
set roll_rate = 18
set pitch_rate = 9
set yaw_rate = 3

# mixer_profile
mixer_profile 1

set platform_type = AIRPLANE
set has_flaps = ON
set model_preview_type = 14

# Mixer: motor mixer

mmix reset

mmix 0  1.000  0.000  0.000  0.000

# Mixer: servo mixer
smix reset

smix 0 1 1 100 0 -1
smix 1 2 0 100 0 -1
smix 2 3 0 100 0 -1
smix 3 4 2 100 0 -1

# battery_profile
battery_profile 1

set throttle_idle =  5.000

# save configuration
save

# end the command batch
batch end

# 

Setup after turn off GPS navigation:

# diff

# version
# INAV/NEXUSX 9.0.1 Feb 13 2026 / 06:53:16 (d44f2cf6) 
# GCC-13.2.1 20231009

# start the command batch
batch start

# resources

# Timer overrides

# Outputs [servo]

# safehome

# Fixed Wing Approach

# features
feature PWM_OUTPUT_ENABLE

# beeper

# blackbox
blackbox -NAV_ACC
blackbox NAV_POS
blackbox NAV_PID
blackbox MAG
blackbox ACC
blackbox ATTI
blackbox RC_DATA
blackbox RC_COMMAND
blackbox MOTORS
blackbox -GYRO_RAW
blackbox -PEAKS_R
blackbox -PEAKS_P
blackbox -PEAKS_Y
blackbox SERVOS

# Receiver: Channel map
map TAER

# Ports
serial 5 2 115200 115200 0 115200

# Modes [aux]
aux 0 0 0 1700 2100
aux 1 1 3 1300 1700
aux 2 12 3 900 1300

# Adjustments [adjrange]

# Receiver rxrange

# temp_sensor

# Mission Control Waypoints [wp]
#wp 0 invalid

# OSD [osd_layout]

# Programming: logic

# Programming: global variables

# Programming: PID controllers

# OSD: custom elements

# master
set looptime = 1000
set gyro_main_lpf_hz = 25
set dynamic_gyro_notch_q = 250
set dynamic_gyro_notch_min_hz = 30
set gyro_zero_x = 1
set gyro_zero_y = 1
set ins_gravity_cmss =  979.547
set gyro_adaptive_filter_min_hz = 20
set acc_hardware = ICM42605
set acczero_x = 1
set acczero_y = -1
set accgain_x = 4083
set accgain_y = 4090
set accgain_z = 4075
set align_mag = CW270FLIP
set mag_hardware = NONE
set baro_hardware = SPL06
set pitot_hardware = VIRTUAL
set blackbox_rate_denom = 2
set motor_pwm_protocol = STANDARD
set small_angle = 180
set applied_defaults = 3
set airmode_type = STICK_CENTER_ONCE
set nav_wp_radius = 800
set nav_wp_max_safe_distance = 500
set nav_rth_allow_landing = FS_ONLY
set nav_rth_altitude = 5000
set nav_fw_control_smoothness = 2
set nav_fw_launch_motor_delay = 100
set nav_fw_launch_max_altitude = 5000
set nav_fw_launch_climb_angle = 25

# control_profile
control_profile 1

set fw_p_pitch = 15
set fw_i_pitch = 5
set fw_d_pitch = 5
set fw_ff_pitch = 80
set fw_p_roll = 15
set fw_i_roll = 3
set fw_d_roll = 7
set fw_p_yaw = 50
set fw_i_yaw = 0
set fw_d_yaw = 20
set fw_ff_yaw = 255
set dterm_lpf_hz = 10
set fw_turn_assist_pitch_gain =  0.400
set nav_fw_pos_z_p = 22
set nav_fw_pos_z_i = 6
set nav_fw_pos_z_d = 2
set nav_fw_alt_control_response = 45
set nav_fw_pos_xy_p = 55
set d_boost_min =  1.000
set d_boost_max =  1.000
set tpa_rate = 80
set rc_expo = 30
set rc_yaw_expo = 30
set roll_rate = 18
set pitch_rate = 9
set yaw_rate = 3

# mixer_profile
mixer_profile 1

set platform_type = AIRPLANE
set has_flaps = ON
set model_preview_type = 14

# Mixer: motor mixer

mmix reset

mmix 0  1.000  0.000  0.000  0.000

# Mixer: servo mixer
smix reset

smix 0 1 1 100 0 -1
smix 1 2 0 100 0 -1
smix 2 3 0 100 0 -1
smix 3 4 2 100 0 -1

# battery_profile
battery_profile 1

set throttle_idle =  5.000

# save configuration
save

# end the command batch
batch end

# 

Here comes another HWFail. But it can be fixed by setting the Pitot Tube to "None."

When GPS navigation is turned off, shouldn't the Pitot Tube also be automatically set to "None" if it was previously set to "VIRTUAL"?

I'm not sure if this is important without GPS...

Ultimately, what matters to me is the ability to use the NEXUS-X/R either as a simple receiver, as a receiver with stabilization, as a receiver with stabilization and RTH, or as a full-fledged flight controller. Thanks to its hardware format, the NEXUS-X/R is ideally suited for introducing beginners to INAV. Of course, HWFail messages can be a bit of a nuisance during that first encounter with INAV...

[Target0815]

Did you turn off "GPS Navigation"?

Yes (in the GPS tab).

[b14ckyy]

Oh the virtual pitot needs GPS yes. Now that you say it there was a discussion if we should turn it on or off by default but I thought it was automatically checked instead if giving an error.

Yeah it was enabled by default but then reverted for the 7.0 release so never should have made it in final. Maybe someone sneaked it back in with another PR and got missed.

#9470

[Target0815]

So is it correct that "Pitot tube = None" should be the default setting if no GPS is configured? And should it also be set to "None" when GPS navigation is disabled?

It would be great if this could be included in the next release.

[b14ckyy]

So is it correct that "Pitot tube = None" should be the default setting

Technically, yes... Personally I never bothered that it was on and thought it was still intentional since I really like it and all my planes have GPS. maybe we can just add a simple logic that turns it off when GPS is disabled. I like to have it on by default. Its calculated in the background anyway and all this Virtual sensor does is, allow the OSD and Programming framework to use the value, that is already there.

[Target0815]

I totally agree with you, and I only fly with GPS too. But this NEXUS-X/R is about the same size as an X8R and can replace the standard receiver in many models. That would be the first step toward getting started with INAV ...

I'm promoting this—check out the following threads:
https://www.rc-network.de/threads/radiomaster-nexus-xr-als-fixed-wing-flightcontroller.12104204/
https://www.frsky-forum.de/forum/index.php?thread/10947-vantac-rf007-mit-inav-als-flight-controller-oder-stabi-empf%C3%A4nger/
https://www.rcgroups.com/forums/showthread.php?4854603-Radiomaster-NEXUS-XR-and-fixed-wing-aircraft

And for beginners, getting started has to be as "foolproof" as possible...

[sensei-hacker]

I hope you got a really good sponsorship deal to promote that as a fixed-wing FC for INAV. It might burn out your credibility permanently. Because it's not a fixed-wing flight controller designed for INAV.

As you may know, an F722 heli controller is the very least capable flight controller available that barely supports some of the features of the INAV. And it's super heavy, four or five times as heavy as a normal flight controller, so it makes small aircraft perform poorly.

Possibly the worst possible choice on the market for most FW use. The folks you are promoting it to may figure that out pretty quickly. Then what does that do to your reputation?

[Target0815]

I'm taking it in stride... I've already suggested to RM that they produce a "NEXUS Extended" (12 PWM ports, H743 processor) ;-).

I don't have any sponsors; I do this for the fun of it, whether using INAV or Arduplane (on Matek hardware).

But you still don't get why the NEXUS is so awesome... I'd prefer it if it already had H743 and so on, but we have to make do with what we've got. @Painless360 already figured that out when he suggested an INAV target.

[Target0815]

By the way, the folks at Rotorflight are also working on a Plane/Wing version of their firmware, which can be configured entirely without a PC—just via LUA on the transmitter. It’ll be interesting to see how this catches on “in the market.”

[sensei-hacker]

I should perhaps clarify - Radiomaster makes good products. They seem to be good people.

That specific product is not designed to be a fixed-wing flight controller, and is not well suited to be used as such. Because it's not supposed to be. It wasn't designed or sold as one. It may be useful in a car or in some special use cases.

My comment above isn't about the product. It's about promoting it as something that it isn't, telling newbies they should buy an F722 heli FC as a fixed-wing FC for INAV, knowing the F722 ran out of space years ago so it can't support modern features and will probably be unusable in nine months. (Or maybe it'll stretch to December 2027 at most).

I'm not saying it's a bad product. I'm saying you wouldn't tell apprentice carpenters to go buy a Kawasaki Ninja. Because motorcycles are not a good choice for carrying lumber. The Ninja is a good motorcycle, it's a terrible choice for carpentry work.

[Target0815]

Just understand that the NEXUS-X/R is the easiest way for glider pilots to get started with INAV. It looks like a regular receiver and can be used as such. That’s much more appealing to potential users than having to solder in various pin headers, not having a proper enclosure, and so on.

Once someone is convinced, they’ll be much more inclined to use a “normal” flight controller, with all its pros and cons.

We don’t need to discuss performance or memory—that’s all clear to me. I run a lot of Arduplane workshops, and every time the problem is that soldering has to be done first. That scares off potential buyers, and that’s exactly where the NEXUS-X/R is different, because it looks just like a normal receiver.

Which flight controller would you recommend to beginners—one that can be used immediately without soldering, comes with a case, and is future-proof? I’m familiar with FCs that meet the criteria for Arduplane, but not for INAV, and certainly not at the price of the NEXUS-X/R, which is also an important factor.

INAV is great software, but I didn't think the maintainer would be so skeptical about it...

[sensei-hacker]

The Holybro Kakute H743-WING is available with headers pre-soldered, and I think the Sologood is also.

I can understand someone being nervous about soldering. That's completely understandable.

Not long ago, I spent a day teaching over 100 people to solder. I'll be doing another event soon. We had a 10-year old who insisted he wanted to do the most complicated kit, which was a whole bunch of small surface-mount components. It took him most of the day but he did it! 😃

Because taking out headers that you don't want is MUCH harder than soldering in headers that you do want, I think most manufacturers do ship with them unsoldered. Dupont plugs take up a LOT of space, with the length of the plug added to the wires sticking out the back, so many people don't want to use them. (But an IDC ribbon cable can allow headers to be used in a more compact build). Some of my test boards have arrived with headers pre-soldered, such as the Blueberry F435, but I don't know if they ship them all that way.

That may be a market opportunity for some other manufacturers - selling them with and without pre-soldered, as Holybro does. I note Raspberry Pi offers the Pico both ways - and I've actually bought Picos both ways.

As you may know, most manufacturers use a PCB cover rather than a metal case, because it saves 90% of the weight:

I don't know any manufacturers who use metal cases for hobby controllers outside of the family of very similar Rotorflight F722 controllers, and I wouldn't expect anyone too. A PCB cover plate does the essentially same thing without bogging down the aircraft with with extra weight and makes it more cost-effective. Adding a full casing made of metal isn't popular - perhaps they think it's a really bad idea? 😄

[sensei-hacker]

Ps re "INAV is great software, but I didn't think the maintainer would be so skeptical about it.."

Consider it from this point of view -
When someone tries INAV, I want them to have a GOOD experience.
I don't want them to spend a bunch of money on a flight controller and then find out it's outdated and won't work with INAV anymore.
I don't want them to build a plane, set everything up, then find out that the cool features they wanted to use aren't available to them, because they have the worst possible flight controller.

I don't want them to see a Rotorflight F722 controller and think "that's small; it will work well in my sub 250. Only to find that the thing comes in a 28 gram casing, so the plane is no longer sub 250, and flies poorly from being overweight.

I am "so skeptical" about setting people up to have a bad experience.