1. Introduction to DJI O4 FPV System Troubleshooting

This guide is designed to provide FPV pilots and builders with a systematic approach to diagnosing and resolving common issues encountered with the DJI O4 and O4 Pro FPV systems. The primary objective is to methodically troubleshoot problems related to video transmission, remote control link, On-Screen Display (OSD) functionality, binding, and other prevalent challenges. By following these steps, users can more effectively determine whether an issue stems from configuration errors, connection problems, firmware incompatibilities, or if it indicates a potential hardware malfunction.

2. Foundational Troubleshooting: The First Steps

Before diving into specific symptom-based troubleshooting, a series of foundational checks must be performed. These steps address the most common and often overlooked causes of FPV system malfunctions. Resolving issues at this stage can save considerable time and effort. The update and activation process for DJI O4 components, in particular, can be an initial hurdle for many users, sometimes masking other problems or even being mistaken for hardware faults if not executed correctly.

Essential Pre-Flight Checks & Initial Diagnostics

• Physical Inspection: Thoroughly inspect all physical connections. This includes the cable between the Air Unit and the flight controller (FC), the coaxial cable connecting the camera to the Air Unit, and the antenna connections to the Air Unit. Look for any signs of pinched, frayed, or damaged cables, as well as loose connectors.
  After any crash, however minor, a detailed inspection for physical damage to any component is crucial.
• Power Supply: Verify that the O4 Air Unit and the Goggles are receiving adequate and stable power according to DJI's specifications. For the O4 Air Unit, ensure the flight controller's BEC (Battery Eliminator Circuit) can supply at least 10W (e.g., 5V at 2A).
  For the O4 Lite, which has a voltage input range of 3.7V to 13.2V, direct power from a 1S LiPo is not recommended due to potential voltage sag; using a stable 5V or 9V BEC from the flight controller is preferable.
  Improper power can lead to intermittent operation, shutdowns, or failure to initialize.
• SD Cards: If using Goggles that require an SD card for DVR recording or firmware updates, ensure the card is compatible (UHS-I Speed Grade 3 or above recommended for recording) and in good health.
  A faulty or improperly formatted SD card can cause recording failures or prevent firmware updates from completing successfully. Note that the O4 Lite Air Unit features internal storage and does not use an SD card.
  For the O4 Pro Air Unit, check if an SD card is used and its status.
• Environment: Be mindful of the operating environment. Large metallic objects, high-power radio frequency (RF) devices, and even dense Wi-Fi networks can cause interference, impacting video and control links.

Firmware: The Backbone of Your System

Firmware is the software that controls the hardware components of your FPV system. Mismatched or outdated firmware is a primary cause of a wide range of issues, including binding failures, video problems, and control link instability.

• Importance of Matched Firmware: It is critical that the O4 Air Unit, DJI Goggles, and DJI FPV Remote Controller all have compatible firmware versions. Ideally, all components should be updated to the latest available firmware from DJI to ensure optimal performance and access to the newest features and bug fixes.
• Updating Process (Air Unit, Goggles, RC):
  • DJI Assistant 2 (Consumer Drone Series): This software is the primary tool for updating firmware on the O4 Air Unit and DJI Goggles.
    Download the correct and latest version from the official DJI website, as the software does not always auto-update, and older versions may not recognize the O4 hardware.
  • Air Unit Power During Update/Activation: The O4 Air Unit must be powered by a LiPo battery connected to the flight controller during firmware updates and activation; USB power alone is insufficient.
    This is a common oversight that leads to update failures.
  • Goggles Update Alternatives: For Goggles, firmware updates can also often be performed by connecting them to a smartphone running the DJI Fly app via an OTG (On-The-Go) cable. This can be a useful alternative, particularly for Mac users who sometimes report issues with DJI Assistant 2 recognizing the Goggles.
• DJI Assistant 2 Common Issues & Fixes: The process of getting DJI Assistant 2 to recognize the O4 Air Unit can be problematic.
  • Device Not Recognized: If the Air Unit is not detected:
    • Ensure you are using a USB data cable, not just a charging cable. Try different cables and different USB ports on your computer, preferably direct ports rather than USB hubs. Some users report success with USB 3.0 (often blue) ports.
    • Verify you have the latest version of DJI Assistant 2 (Consumer Drone Series).
    • Experiment with connection sequences: e.g., power the quadcopter (with the Air Unit installed and powered) first, then connect the USB cable to the computer.
    • Try reinstalling DJI Assistant 2, possibly with administrator privileges, or logging out and back into your DJI account within the software.
    • Some Bind-N-Fly (BNF) drones with O4 Lite / O4 Pro may come pre-activated from the manufacturer as they need to activate the units during testing.
  • Activation Link Not Appearing: This can occur if the unit is already activated or if DJI Assistant 2 is not correctly recognizing the device or its status.

Activation: Getting Your O4 System Online

New DJI O4 Air Units typically require activation before they can be used to their full potential. Failure to activate can result in limitations such as reduced transmission power, no HD video output, or inability to bind.

• Process: Activation is performed using DJI Assistant 2 (Consumer Drone Series) while the Air Unit is connected to the computer via USB and powered by a battery.
  Follow the on-screen prompts within the software.
• Common Pitfalls: Users may not be aware that activation is necessary or that the process has failed. As mentioned, the Air Unit must be powered externally from a battery.
• Troubleshooting Activation: If activation fails or the option doesn't appear:
  • Revisit all troubleshooting steps for DJI Assistant 2 device recognition.
  • Ensure the Air Unit's firmware is up-to-date. Sometimes, a successful firmware update must occur before the activation prompt becomes available in DJI Assistant 2.
  • Logging out of DJI Assistant 2, selecting the device, and then being prompted to log back in has resolved activation issues for some users.

3. Diagnosing Video Feed Problems

A clear and stable video feed is the cornerstone of the FPV experience. Issues can range from a complete lack of video to poor quality, low bitrate, or image instability.

No Video Signal / Black Screen in Goggles

A black screen in the Goggles is a common and frustrating issue. Troubleshooting should proceed methodically:

• Basic Checks:
  • Power and Link Status: Confirm that both the Goggles and the Air Unit are powered on. Check the LED status indicators on the Air Unit to verify its operational state and binding status (refer to Table 1 in Section 6 for LED codes).
    Ensure the Goggles are correctly linked to the Air Unit.
  • Goggles Mode/Input Source: If your Goggles support multiple DJI systems (e.g., O3 and O4), ensure the correct mode for the O4 Air Unit is selected in the Goggles settings. For instance, DJI Goggles 3 users need to select "DJI O4 Air Unit" under Status > Switch if they previously used an O3 unit.
  • Camera Connection: The coaxial cable between the camera and the Air Unit is a frequent culprit. Inspect it meticulously for any signs of pinching, sharp bends (especially at the connector base), physical damage, or if it's not fully seated at both ends.
    Even a slightly loose connection can result in no video. If accessible, try reseating the cable.
  • Air Unit Overheating: The O4 Air Unit generates significant heat and can shut down or cease video transmission if it overheats, especially during prolonged ground testing without adequate airflow.
    Ensure it's installed with proper ventilation.
• Advanced Checks:
  • Cable Replacement: If damage to the camera coaxial cable is suspected and it's detachable, try replacing it with a known good one. Some users have resolved black screens or "IMU Error" messages that appeared after a crash by replacing the camera cable.
  • Camera Test: If possible, test the Air Unit with a different, known-good O4 camera, or test the suspect camera on a known-good O4 Air Unit to isolate the faulty component.
  • OSD Presence: If OSD elements are visible in the Goggles but there's no camera image, the problem likely lies with the camera itself or its direct connection to the Air Unit. If there is no OSD and no video, the issue could be more systemic, involving the Air Unit, its power supply, or the link to the Goggles.
  • Post-Crash Failures: A black screen appearing immediately after a crash, sometimes accompanied by other errors like "IMU Error" after a subsequent firmware update attempt, strongly suggests physical damage to the Air Unit or camera module, even if not immediately visible.

Addressing Low Bitrate and "Ham File" Issues (Goggles 2/Integra)

A specific and widely reported issue affects users of the DJI O4 Pro or O4 Lite Air Units when paired with DJI Goggles 2 or DJI Goggles Integra, particularly when attempting to use a community-created "ham file" (often named ham_cfg_support). This file is intended to unlock FCC-level transmission power and additional channels, especially for users in CE-regulated regions.

• The Problem: Instead of achieving the expected 50 Mbps bitrate with the O4 system, users find their bitrate capped significantly lower, often around 15 Mbps, though sometimes observed between 16-31 Mbps.
  This results in a choppy, "slideshow-like" video feed, severely degrading the FPV experience.
• The Cause: The issue arises from an incompatibility or bug in how the Goggles 2/Integra firmware interacts with the O4 Air Unit when the ham file is active and the Goggles are in "Auto" channel mode. The system fails to correctly switch to the necessary 40MHz carrier mode, limiting bandwidth.
• Workarounds: Since the ham file is an unofficial modification, an official fix from DJI is unlikely.
  Users have developed the following workarounds:
  1. Reset Goggles: This reverts the Goggles to their default regional settings, removing the effects of the ham file. Navigate to Settings > About > Reset All in the Goggles menu. Crucially, before resetting, remove the SD card containing the ham file from the Goggles, or format the SD card. If the ham file is present during reboot, the issue will persist.
     This workaround restores normal bitrate but sacrifices the FCC power/channel benefits of the ham file.
  2. Manual Channel Mode: Instead of using "Auto" channel mode, switch to "Manual" in the Goggles' transmission settings. Manually select a channel and set the bandwidth to 40MHz (or 60MHz if your Goggles and region support it with O4). This can allow the system to achieve the full 50 Mbps bitrate while still benefiting from the ham file's power unlock.
     The downside is the loss of automatic channel switching, which can be problematic in environments with varying RF interference.
  3. Upgrade to DJI Goggles 3: For users who require FCC-level performance and wish to avoid these workarounds, upgrading to DJI Goggles 3 is often cited as the most reliable long-term solution, as they are designed with native O4 support and generally do not exhibit this specific ham file-related bitrate cap.

The "ham file" situation illustrates a common theme in the FPV world: users often seek to push hardware beyond its officially sanctioned regional limits for improved performance. This can lead to community-developed solutions that, while effective for one aspect (like power output), may introduce unintended side effects or incompatibilities with other system functions, as seen with the Goggles 2/Integra bitrate cap.

Tackling Video Jello, Vibration, and Stabilization Issues

• Troubleshooting RockSteady / Gyroflow:
  • IMU Resonance Test (Props Off): This helps determine if vibrations are causing the camera's IMU to resonate, which can corrupt stabilization data.
    1. Securely mount the camera. Remove all propellers from the drone.
    2. Place the drone on a stable surface.
    3. In the Goggles menu, enable RockSteady (or ensure stabilization is set correctly if planning to use Gyroflow later). Start recording video.
    4. Slowly increase motor throttle to full. Observe the live view in the Goggles; it might appear stable.
    5. Stop the motors, stop recording, and review the recorded footage. If the recorded video is shaky or exhibits jello, IMU resonance is likely the cause.
    • Solutions for IMU Resonance:
      • Change ESC PWM Frequency: The default ESC PWM frequency (often 24kHz) can sometimes coincide with the camera IMU's natural frequency. Changing the ESC PWM frequency in your flight controller software (e.g., Betaflight, BLHeliSuite) to 48kHz or 96kHz can shift the vibration frequency away from the sensitive range.
        This is often a very effective fix.
      • Improve Camera Damping: Ensure the camera is soft-mounted using appropriate materials like TPU (thermoplastic polyurethane) prints, rubber grommets, or silicone spacers. Avoid rigid mounting directly to the carbon fiber frame.
        The O4 Lite may require softer damping than the O4 Pro due to weight differences.
      • Camera Cable Management: Ensure the camera cable itself is not taut or positioned in a way that transmits vibrations from the frame to the camera.
  • Propeller Vibration Test (Props On): If both the live view in the Goggles and the recorded footage exhibit jello or rolling shutter, the issue is more likely due to general propeller and motor vibrations being transmitted through the frame.
    • Solutions for Propeller Vibration:
      • Balance Propellers: Unbalanced propellers are a major source of vibration. Use a prop balancer to balance each propeller.
      • Inspect Propellers: Ensure propellers are not chipped, bent, or otherwise damaged. Replace if necessary.
      • Motor Condition: Check motors for bent shafts or rough bearings.
      • Frame Integrity: Ensure the drone frame is rigid and all screws are tight.
      • Adjust Camera Damping/Screw Tightness: Experiment with the tightness of screws securing the camera and the type/density of soft-mounting material.
  • Antenna Vibrations: Ensure antennas are securely mounted and not flapping, as this can also introduce vibrations.
  • Gyroflow Specifics: If using Gyroflow for post-stabilization, ensure "Recording Stabilization" is set to OFF in the Goggles menu. Recommended recording settings for Gyroflow often include a 4:3 aspect ratio and Wide camera FOV.

Eliminating On-Screen Noise and Static

Electrical noise or poor signal integrity can manifest as static, lines, or general degradation of the video image.

• Causes:
  • Poor electrical connections to the Air Unit.
  • Insufficient power filtering on the drone's power distribution board (PDB) or flight controller.
  • Loose or damaged camera coaxial cable.
  • Loose or damaged antenna U.FL connections on the Air Unit.
  • Interference from other electronic components on the drone.
• Solutions:
  • Reseat Cables: Carefully reseat the camera coaxial cable at both the camera and Air Unit ends. Ensure the connectors are clean and fully engaged. Some users have found that applying gentle pressure with tape to the coax connector on the Air Unit side resolved static issues.
  • Clean Power Supply: Ensure the Air Unit is powered from a clean and stable voltage source. If electrical noise is suspected, consider adding a dedicated BEC (e.g., a 9V BEC) to power the Air Unit, or ensure a sufficiently large capacitor (e.g., 1000-1500µF, appropriate voltage rating) is correctly installed on the main battery pads of the FC/PDB.
  • Secure Antenna Connections: Verify that the U.FL antenna connectors are securely attached to the Air Unit. These can sometimes become loose, especially after a crash.
  • Cable Routing: Route signal and power cables away from high-noise components like ESCs if possible.

Video quality problems in the O4 system are rarely due to a single cause. They often arise from an interplay of firmware behavior (like the Goggles 2 bitrate cap), the physical build of the drone (vibration management, cable integrity), and electrical factors (power supply cleanliness). The O4 system's heightened sensitivity to vibrations, for example, means that build quality and component isolation are more critical than they might have been with previous FPV systems. Therefore, a multi-pronged diagnostic approach is necessary, differentiating between symptoms like low bitrate (likely firmware/setting related), jello (likely mechanical/vibration related), and static/black screen (often connection or power related), as their solutions are distinct.

4. Resolving RC Signal and Control Issues

A reliable remote control (RC) link is essential for safe and responsive flight. Problems can range from a complete lack of stick inputs in the flight controller software to intermittent signal loss or limited range.

No Remote Controller Inputs Detected (Especially in Betaflight)

This is a common setup issue, particularly when integrating the DJI O4 Air Unit (which can act as an RC receiver) with a Betaflight flight controller.

• Binding: First and foremost, ensure the remote controller is correctly bound to the Goggles, and the Goggles are correctly bound to the Air Unit. If your DJI remote controller model supports direct binding to the Air Unit, ensure that link is established according to DJI's instructions.
• Betaflight Configuration (Critical):
  • Receiver Protocol: In Betaflight Configurator, navigate to the "Receiver" tab. Ensure "Receiver Mode" is set to "Serial-based receiver." For the "Serial Receiver Provider," select "SBUS".
    The default setting in Betaflight is often CRSF, which is incorrect for the DJI internal receiver.
  • Ports Tab: Go to the "Ports" tab in Betaflight. Identify the UART (Universal Asynchronous Receiver/Transmitter) on your flight controller to which the Air Unit's SBUS wire is connected. For that specific UART, enable the "Serial RX" toggle.
    Ensure no other function (like MSP for OSD, unless specifically configured for shared use if supported by the FC and Betaflight version) is conflicting on this UART if it's dedicated to SBUS.
  • Wiring: Double-check the physical wiring. The SBUS output wire from the Air Unit's harness must be connected to an available RX (receive) pad on the flight controller that corresponds to the UART configured for Serial RX.
  • sbus_baud_fast Setting: This Betaflight CLI (Command Line Interface) setting has been a point of contention and potential confusion.
    • Some users and guides recommend setting set sbus_baud_fast = ON in the CLI and enabling a corresponding "SBUS Fast Baud" option in the DJI Goggles settings (Settings > Control > SBUS Baud Fast).
    • However, other users, particularly those using the DJI FPV Controller 2 with an O4 Air Unit, found that setting set sbus_baud_fast = OFF in the CLI was necessary to resolve stick input issues or "Remote Control Stick Error" messages.
    • This discrepancy suggests the optimal setting may depend on the specific combination of DJI controller model, Goggles firmware, O4 Air Unit firmware, and Betaflight version. If experiencing no RC inputs, it is advisable to try both ON and OFF for this setting.
  • Channel Mapping: In the Betaflight "Receiver" tab, verify the "Channel Map" (e.g., AETR1234, TAER1234). This must match the channel order output by your DJI remote controller. For DJI systems, TAER1234 is common, but it's worth verifying.
• Firmware Compatibility: Ensure the flight controller firmware, Air Unit firmware, Goggles firmware, and Remote Controller firmware are all up-to-date and mutually compatible.
  In some cases, re-flashing the flight controller firmware while ensuring the SBUS protocol is explicitly selected during the build process (if using custom firmware builds) might be necessary, as some pre-compiled firmwares might omit certain protocols to save storage space.
• Hardware Issues: Inspect the SBUS wire and its connectors for any damage or loose connections.

Troubleshooting Weak or Intermittent RC/Video Signal (Range Problems)

Limited range or sudden signal dropouts can be alarming and dangerous. Several factors contribute to signal strength and reliability:

• Antenna Orientation (RC & Aircraft):
  • Remote Controller Antennas: The flat plane of the remote controller's antennas should generally face the aircraft. Avoid pointing the tips of the antennas directly at the drone, as this is often a null (weakest signal) point.
    Maintain proper antenna orientation, such as a "V" shape or parallel like "11," and avoid crossing them into an "X".
  • Aircraft Antennas: The placement and orientation of the Air Unit's antennas on the drone are critical. They should extend out of the aircraft frame, be unobstructed by carbon fiber, the battery, or other metallic components, and be clearly visible from multiple angles.
    Poor placement can lead to signal blockage, especially during certain maneuvers or orientations of the drone relative to the pilot.
• Environmental Factors:
  • Obstacles: Physical obstructions like trees, buildings, hills, or even the pilot's own body can significantly attenuate the signal.
    Maintaining a clear line of sight is crucial. If signal is lost behind an obstacle, try to fly the aircraft to a higher altitude to regain connection.
  • Wireless Interference: Flying in areas with high RF interference (e.g., urban environments with many Wi-Fi networks, near cell towers, or close to other FPV pilots transmitting on similar frequencies) can degrade signal quality and range.
  • Flying with Others: When flying with other pilots, especially those using different FPV systems, consider using narrower bandwidth settings (e.g., 20MHz in Race Mode if available) and potentially reducing transmission power to minimize cross-interference.
• FCC vs. CE Mode: DJI equipment sold or operated in CE (European Conformity) regions is typically limited to lower transmission power (e.g., 25mW) compared to FCC (Federal Communications Commission) regions. This significantly impacts range.
  Using a "ham file" or other community-developed methods can unlock FCC-level power on the Goggles, but users must be aware of and comply with local regulations.
• Hardware Issues:
  • Damaged antennas on the remote controller or the Air Unit.
  • Loose or damaged U.FL antenna connectors on the Air Unit (a known vulnerability, especially on the O4 Pro).
  • A faulty Air Unit or remote controller can also lead to persistent signal problems.
• Firmware: Keeping all system components (RC, Goggles, Air Unit) updated to the latest firmware versions can sometimes improve signal stability and range, as DJI may release optimizations.

The challenge in diagnosing range issues often lies in the complex interplay of these factors. A user might have perfect line-of-sight but poor RC antenna orientation, or be in a clear area but unknowingly operating in low-power CE mode. A systematic check, moving from the easiest verifications (like RC antenna pointing) to more involved ones (inspecting aircraft antenna mounting, considering FCC mode implications), is necessary.

Addressing "Remote Control Stick Errors"

The "Remote Control Stick Error" message appearing in the Goggles' OSD typically points to an issue with the remote controller's gimbals (sticks) or their calibration. However, it can also be related to the communication link or specific software settings.

• One user reported this error appearing when a particular switch was flipped on their DJI FPV Controller 2 used with an O4 Air Unit, even though other stick inputs were not registering. The solution, in that specific case, was to set sbus_baud_fast = OFF in the Betaflight CLI.
• Recalibrate Sticks: Perform a stick calibration procedure through the DJI Goggles or remote controller settings menu.
• Physical Inspection: Check the remote controller's gimbals for any physical obstruction, damage, or excessive wear.
• If the error persists after calibration and checking the sbus_baud_fast setting, it could indicate a hardware fault within the remote controller itself.

5. Troubleshooting On-Screen Display (OSD) Malfunctions

The On-Screen Display provides crucial flight information directly in the FPV feed. When OSD elements from Betaflight (or other flight controller software like INAV) fail to appear, it's usually due to incorrect wiring or configuration.

Betaflight OSD Elements Not Appearing

This is a frequent challenge for pilots setting up a new build or after firmware changes.

• Wiring (TX from FC to RX on Air Unit, and potentially RX from FC to TX on Air Unit): This is the most critical aspect for Betaflight OSD.
  • OSD data is transmitted from the flight controller's TX (transmit) pad to the Air Unit's RX (receive) pad using the MSP (MultiWii Serial Protocol). Ensure this wire is correctly connected.
    A common mistake is wiring TX-to-TX and RX-to-RX; it must be crossed (TX-to-RX, RX-to-TX).
  • For some OSD features, like detecting arming status or allowing the VTX to send commands to the FC, bidirectional communication might be needed. This means the Air Unit's TX pad should also be connected to an RX pad on the FC.
    While OSD primarily relies on FC TX to VTX RX, full functionality might require the return path.
• Betaflight "Ports" Tab Configuration:
  • Identify the UART on the flight controller to which the Air Unit's OSD wires are connected.
  • In the "Ports" tab, for that specific UART, enable "MSP" under the "Configuration/MSP" column.
  • In the "Peripherals" column for the same UART, select "VTX (MSP + Displayport)" or a similar option indicating it's for a digital VTX.
• Betaflight "OSD" Tab:
  • Ensure the main "OSD" toggle is enabled.
  • Under "Video Format," select "HD".
    Analog or other settings will not work correctly with the DJI system.
  • Verify that the desired OSD elements (e.g., battery voltage, timer, craft name) are enabled and dragged onto the visual layout.
• Betaflight Presets: Betaflight Configurator offers a "Presets" tab. Searching for a preset like "osd for dji" or "walksnail osd" (as some digital VTX presets are similar) can often automatically configure the necessary OSD settings. When applying such a preset, ensure options like "map to displayport," "set HDOSD," and the correct UART are selected.
• Goggles Settings: In the DJI Goggles display settings, ensure that "Custom OSD" or "HD Canvas" (if available as an option) is enabled to allow Betaflight OSD elements to be displayed.
• Betaflight Firmware Compilation: When flashing Betaflight firmware, especially custom builds or versions for flight controllers with limited memory, ensure that OSD support was included in the compilation. If OSD features were omitted to save space, they will not be available.
  Reflashing with OSD enabled might be necessary.
• Faulty Hardware: While less common, a faulty UART on the flight controller or an issue with the OSD processing capabilities of the Air Unit could be the cause if all software and configuration steps have been meticulously verified. Some users have reported instances where, with identical settings, one O4 unit displayed OSD while another did not, suggesting potential hardware variance or defect.

The successful display of Betaflight OSD elements hinges on a precise alignment of physical wiring (particularly the correct TX/RX connections for MSP), correct UART configuration in the Betaflight "Ports" tab, and appropriate settings in both the Betaflight "OSD" tab and the DJI Goggles. These three areas are where most OSD-related setup errors occur.

Understanding INAV OSD Support and Current Status with O4

INAV (Navigation-enabled flight control software) is popular for its autonomous flight capabilities, waypoint navigation, and robust Return-to-Home (RTH) features.

• Initial Lack of Support: When the DJI O4 system was first released, it did not officially support INAV OSD. It was primarily focused on Betaflight compatibility. Users attempting to use O4 with INAV reported issues, such as the inability to arm the drone, often attributed to differences in how DJI implemented the MSP protocol compared to what INAV expected.
• Official INAV OSD Support Added: Subsequently, DJI released firmware updates for its Goggles lineup that introduced official INAV OSD support when used with the DJI O4 Air Unit or O4 Air Unit Pro.
  These updates were:
  • DJI Goggles 3: Firmware v01.00.0800 or newer
  • DJI Goggles 2: Firmware v01.12.0000 or newer
  • DJI Goggles Integra: Firmware v01.08.0000 or newer
• Requirements for INAV OSD with O4:
  • Update the Goggles firmware to the specified versions (or later).
  • Update the DJI Fly app (used for Goggles firmware updates) to version 1.16.0 or newer.
  • Ensure the O4 Air Unit firmware is also up-to-date and compatible.
  • Correct wiring between the flight controller (running INAV) and the O4 Air Unit is essential. As with Betaflight, this typically involves connecting the FC's TX to the Air Unit's RX for OSD data transmission. For full functionality, including arming status and other MSP communications from the VTX to the FC, the Air Unit's TX may also need to be connected to an FC's RX.
  • Proper port configuration in INAV (enabling MSP on the correct UART) is also necessary.
• Benefits of INAV OSD with O4: This integration allows pilots to see advanced telemetry data, navigation cues for waypoints, and more detailed RTH information directly in their FPV feed, enhancing situational awareness and control for navigation-focused flights.
• Troubleshooting INAV OSD: If INAV OSD is not working despite having the correct firmware versions:
  • Double-check all wiring between the FC and Air Unit.
  • Verify port configurations in INAV Configurator, ensuring MSP is enabled on the correct UART and set to communicate with the VTX.
  • If problems persist, it might be due to subtle differences in MSP implementation specific to O4 that INAV developers or DJI may still need to refine.
    Consulting INAV community forums or DJI support would be the next step.

The journey of INAV support for the O4 system—from initially unsupported to officially supported via firmware updates—highlights the dynamic nature of FPV software and hardware integration. It underscores the importance for users to keep all components of their system updated to the latest firmware to access new features and compatibility improvements.

6. Solving Binding Failures

Binding is the process of establishing a wireless link between the Air Unit, Goggles, and Remote Controller. Failures in this process can prevent the system from functioning at all. Binding issues often arise from a cascade of unmet prerequisites: incompatible hardware, mismatched or outdated firmware across components, incomplete activation of the Air Unit, or not following the correct binding sequence. A pre-binding checklist covering these prerequisites is highly recommended.

Air Unit Not Binding with Goggles

• Compatibility and Goggles Mode:
  • Ensure your DJI Goggles model is compatible with the DJI O4 Air Unit (see Table 2).
  • Crucially, ensure the Goggles are set to the correct operating mode for the O4 system. For example, if using DJI Goggles 3, navigate to Status > Switch and select "DJI O4 Air Unit." If the Goggles were previously used with an O3 unit or are in a different mode, they will not bind to an O4 Air Unit.
    This small step is easily overlooked and a common cause of binding failure.
• Firmware: All devices involved (Air Unit and Goggles) must have up-to-date and, most importantly, compatible firmware versions.
  Update both using DJI Assistant 2 (Consumer Drone Series) or the DJI Fly app for Goggles where applicable.
• Binding Procedure:
  1. Power on the DJI Goggles.
  2. Power on the O4 Air Unit. The Air Unit must be powered by a LiPo battery connected to the drone/FC; USB power is insufficient for binding.
  3. Place the Goggles into binding mode. This usually involves pressing a dedicated link button or a sequence of button presses, after which the Goggles will typically start beeping continuously.
  4. Press the bind button on the O4 Air Unit. The Air Unit's LED status indicator should change, often from solid red to flashing red, indicating it's in binding mode. Upon successful binding, the LED will typically turn solid green, the Goggles will stop beeping, and the camera feed should appear.
     (Refer to Table 1 for LED indicator details).
• Proximity and Interference: Ensure the Goggles and Air Unit are reasonably close to each other (e.g., within 0.5 meters) during the binding process. Attempt binding in an environment with low radio frequency (RF) interference.
• Activation Status: Ensure the O4 Air Unit has been successfully activated using DJI Assistant 2. An unactivated unit may fail to bind or operate correctly.
• Hardware Issues: While less common, a hardware fault in either the Goggles or the Air Unit could prevent binding. One user reported an O4 Air Unit Pro that would not bind to Goggles 3 but did bind to older Goggles models, suggesting a potential specific compatibility flaw or a faulty unit, though this could also be a very specific firmware mismatch.

Remote Controller Not Linking with Goggles/Air Unit

• Compatibility: Verify that your DJI FPV Remote Controller model is compatible with your Goggles and the O4 system (see Table 2). The DJI FPV Controller 3 is designed for the O4 system and Goggles 3. The DJI FPV Controller 2 can be made compatible with the O4 system via a firmware update.
• Firmware: All three components—Remote Controller, Goggles, and Air Unit—must have compatible and preferably up-to-date firmware versions.
• Linking Sequence (Important):
  • For most DJI FPV setups, the general sequence is:
    1. Link the Air Unit to the Goggles first.
    2. Once the Air Unit and Goggles are successfully linked, then link the Remote Controller to the Goggles.
  • Some DJI integrated drones (like the Avata series) might have specific pairing sequences or allow direct RC to drone linking; always refer to DJI's official instructions for your specific equipment.
• Binding Procedure (RC to Goggles):
  1. Power on both the Goggles and the Remote Controller.
  2. Place both devices into linking/binding mode simultaneously. This often involves long-pressing their respective power buttons or dedicated link buttons until they start beeping or their status LEDs indicate they are searching.
  3. Wait for the devices to establish a link. Successful linking is usually indicated by the beeping stopping, status LEDs turning solid, and the Goggles displaying the live view (if already linked to an Air Unit) or remote control information.
• Battery Levels: Ensure all devices (Goggles, RC, Air Unit) have sufficient battery charge before attempting to bind. Low battery levels can sometimes cause unexpected behavior.

Understanding the status LEDs on the O4 Air Unit is crucial for diagnosing binding and operational issues.