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General Questions

Awesome! Now with virtually no range limit how can I further increase my flight time?

🅰️ There are a lot of battery mods available for the Parrot Disco. Some people managed to get more than 3 hours of flight time with bigger batteries. We also have a dedicated channel #batteries in our Slack community. Sounds like the perfect combination for the 4G/LTE mod. 😄

What is the latency like compared to the normal Wi-Fi connection?

🅰️ Typically for direct connections (see this FAQ entry), the latency is around 50 ms. The pre- and post-processing of the live video stream is more than that, which you will also experience when flying in the original set-up (over Wi-Fi).

My question is not covered in here, can you help me?

🅰️ Feel free to contact us! We will constantly try to add more relevant questions and answers to this FAQ

How much data per hour is required? / What bandwidth is required?


Video stream resolution Data usage Bandwidth required
480p ~1.1 GB/hour ~2.4 Mbit/s
720p ~2.2 GB/hour ~4.8 Mbit/s

👉 to switch resolution, change the recording resolution in FreeFlight Pro.
If recording is set to 1080p, the live video stream will be 480p (default in FeeFlight Pro)
If recording is set to 720, the live video stream will be 720p
The data rate can be further reduced, but requires some manual scripting.

⚠️ Note: the data usage will arise on both SIM cards. Hence, you might get charged twice for the data usage mentioned above (depends on your operator).

Is it possible to use the softmod just for real-time location tracking via GPS, but not for video/controls/telemetry? (e.g. to save mobile data)

🅰️ Absolutely! All you need is to open the Glympse link received via SMS/Push Notification once the Disco is started. As long as the 4G mode is not initiated via double press on Settings, your Skycontroller 2 will stay on Wi-Fi (green LED). Just fly as usual.
If you never want to use the option for 4G/LTE video/controls/telemetry, you can ignore the following installation steps entirely:

  • A mobile tethering device is not required.
  • ZeroTier account does not need to be created.
  • The following config files do not require to be set:
    • disco/uavpal/conf/zt_networkid
    • skycontroller2/uavpal/conf/wpa
    • skycontroller2/uavpal/conf/ssid
    • skycontroller2/uavpal/conf/zt_networkid
  • /tmp/disco4g/skycontroller2/ does not need to be run (double pressing the Settings button will have no effect)
  • All steps after reboot can be ignored

Does it work on 3G as well? Is there a seamless switch-over from 4G to 3G in case there is no 4G network coverage?

🅰️ Yes, but it has not been thoroughly tested. For best performance 4G/LTE is recommended.

Are there any other charges than the mobile data?

🅰️ Depending on your mobile network operator, you might get charged for the SMS containing the Glympse link for GPS tracking and/or microSD card insertion/removal notifications.

How can I record videos and photos to a microSD card instead of the internal storage (which is limited to 32 GB)?

🅰️ You need a microSD card (formatted as FAT32). Once you insert it into the Huawei modem (most models come with an integrated microSD card reader, such as the E3372), the Disco will automatically record videos and photos to it. The Huawei modem itself needs to be plugged into CHUCK via the USB OTG cable.

  • Whenever a microSD card is inserted into the modem, the Disco's power button LED will change its color from orange → green → cyan → blue → magenta quickly to indicate that videos and photos will now be recorded to the microSD card.
  • Whenever a microSD card is removed from the modem (or the Disco could not detect/mount the file system), the Disco's power button LED will flash red three times. This indicates that all videos and photos will be recorded to the internal storage.

In addition, the Disco will send a Push Notification/SMS for the events above to your mobile device (if configured).

⚠️ Note: this feature only works on the latest Disco firmware version (1.7.1).

⚠️ Note: there are different speed classes of (micro)SD cards:

For 720p video recording, you will require at least an

  • SDHC Class 10 (Symbol: "10", minimum sequential write speed: 10 MB/s)

For 1080p video recording, you will require at least an

  • SDXC I UHS Speed Class 3 (Symbol: "U3", minimum sequential write speed:30 MB/s)
  • SDXC II Video Speed Class 30 (Symbol: "V30", minimum sequential write speed: 30 MB/s)

👉 Windows users need the tool guiformat.exe to format drives bigger than 32 GB in FAT32.

Does this softmod work on the Parrot Bebop 2 as well?

🅰️ Yes, it does! Head over to #BebopTwo4G

Can I use the softmod on my Disco and Bebop 2 with the same Skycontroller 2?

🅰️ Yes. If the softmod is already installed on your Skycontroller 2, you can safely ignore the installation steps for the controller (i.e. Make sure you use the same ZeroTier network ID (conf/zt_networkid) for all three devices!

Why did you chose blue LED on Skycontroller 2 to indicate 4G/LTE mode?

🅰️ Inspired by Rambo III

Is UAVPAL in any way affiliated to Parrot Drones SAS?

🅰️ Nope.


Which Huawei E3372 model is right for me?

🅰️ There are different models of Huawei E3372 modems: 153, 210, 510, 607. E.g. E3372h-153 is a very common one. Different models support different LTE bands. This is important as most countries regulate frequencies and therefore only a set of LTE bands is available in certain countries, of which again mobile network operators might only use a subset.

E3372 Model LTE Band supported should* work in
153 and 210 1,3,7,8,20 Africa, Asia, Central and South America, Caribbean, Europe, Middle East, Oceania
510 1,2,4,5,7,28 US (excluding Sprint)
607 1,3,7,8,28,40 Africa, Asia, Central and South America, Caribbean, Europe, Middle East, Oceania, Russia

*This is only a guideline, you should double check our list of Known Working Mobile Carriers and Settings where we recommend specific modem models per carrier. Or check out LTE bands used by your mobile network operator and make sure you buy a model that covers at least one supported LTE band.

Huawei E3372 modems are available in two different flavors, Hi-Link mode (firmware 22.x) and Stick mode (firmware 21.x). Both firmware versions can be found on E3372s and E3372h hardware types:

  • E3372s is slightly older and comes mostly (but not exclusively) in Stick mode.
  • E3372h is newer and comes mostly (but not exclusively) in Hi-Link mode. A conversion between Stick and Hi-Link mode is possible in most cases, but the process is not straight-forward.

Both types work with the 4G/LTE softmod. We recommend the E3372h modem with Hi-Link.

Can I use other USB modems than the Huawei E3372?

⚠️ Note: the newer E3372h-320 model does not work with the softmod currently. Some sellers on Amazon advertise the E3372h-320 as E3372h-153!

🅰️ The following Huawei modems have been reported to work well with the 4G/LTE softmod:

  • E3372h, E3372s
  • MS2372h
  • E8372h
  • E3276s

👉 for the E3276s and MS2372h, you need to swap the values (0 and 1) of the variables serial_ctrl_dev and serial_ppp_dev in /data/ftp/uavpal/bin/

What does the Huawei E3372 modem's LED indicate?


  • Green, flashing twice every 2s: The USB-Modem is powered on.
  • Green, flashing once every 0.2s: The software of the USB-Modem is being upgraded.
  • Green, flashing once every 2s: The USB-Modem is registering with a 2G network.
  • Blue, flashing once every 2s: The USB-Modem is registering with a 3G network.
  • Cyan, flashing once every 2s: The USB-Modem is registering with a 4G network.
  • Green, solid: The USB-Modem is connected to a 2G network.
  • Blue, solid: The USB-Modem is connected to a 3G network.
  • Cyan, solid: The USB-Modem is connected to a 4G network.

What happened to the Raspberry Pi?

🅰️ Right! In the first Youtube video uploaded, there was a Raspberry Pi required to bridge the connection from the Skycontroller 2 to the tethering device. We managed to find a solution without the RPi.
RIP RPi! 😥

How much extra power does the 4G/LTE modem consume?

🅰️ The Huawei E3372 modem draws 0.10A - 0.15A under full load, whereby the Disco consumes

  • maximum (e.g takeoff): 15.5A
  • average: 3.6A (based on Parrot's "45 minutes" specification)
  • C.H.U.C.K. without motor running: 0.7A

Therefore, the power consumed by the 4G/LTE modems is not significant (less than 5%). Additionally, not fully utilizing the Wi-Fi antennas during a 4G/LTE flight, saves a fair bit of power as well.

Where can I purchase the hardware?

🅰️ We provided links to order the required hardware from Amazon and AliExpress under the Requirements Section. Look out for the "Buy now!" links.

The Micro USB port on CHUCK chipped off. Is there a way to fix it?

🅰️ Yes, please refer to the Wiki article: How to fix a broken Micro USB port on CHUCK

Operating Disco over 4G/LTE

Isn't the extra hardware too heavy for the Disco?

🅰️ No, the modem with cable and antennas only weighs 43g. The Disco can handle it without a problem.

Is it possible to connect the Skycontroller 2 to a home Wi-Fi network instead of a mobile tethering device (so you only have to use one data plan)?

🅰️ Absolutely! For lowest latency, we still recommend to go with a mobile tethering device. But we have received feedback from users who are very happy with the home Wi-Fi option. If possible, the home broadband connection should be the same ISP/carrier as the SIM card in the Disco's USB modem.
If Glympse indicates your connection being relayed [R], you can try to add a port forwarding rule on your home Wi-Fi Router/Access Point for incoming connections on UDP port 9993 to the LAN IP address of your Skycontroller 2. This should give you a [D] direct (low latency, full throughput) connection.

What if the 4G/LTE connection gets interrupted during a flight?

🅰️ Usually when the video stream starts to get choppy, you are approaching a not spot (area with no mobile phone reception, or not enough bandwidth available). If your 4G/LTE connection gets interrupted, your Disco will initiate a Return-to-Home (RTH) after a few seconds. This will normally bring back the connection (video stream and controls). In the worst case scenario that there is no reconnection, the Disco will fly back to the take-off point and initiate auto-landing. It might be advisable to change to Wi-Fi mode as soon as the Disco is in sight so you can take over for a controlled landing.

My video streams gets choppy in certain areas, but FreeFlight is still showing full signal bars. Why?

🅰️ The signal bars in FreeFlight Pro show the strength of your Wi-Fi connection only. Your Wi-Fi connection is from Skycontroller 2 to your tethering device (probably mobile phone in your pocket). You most likely will always see full bars.

What if the Wi-Fi connection to the tethering device is lost/interrupted during a 4G/LTE flight?

🅰️ The LED on Skycontroller 2 will start to flash red. Currently, there is no auto-reconnect. You will need to manually switch into Wi-Fi mode and then back to 4G/LTE mode. By doing so, it will re-initiate the Wi-Fi connection to your tethering device.

I can't seem to fly past the 2 km mark without my Disco turning around. Why?

🅰️ You need to disable Geofence in FreeFlight pro under Setting/Safety. Please note, this will also disable the minimum altitude!


Where can I find the Release Notes (Change Log) and links to download older releases?

🅰️ Release Notes and Download Archives can be found here.
If you are interested in the latest Beta version, check out this FAQ article.

Do I need to reinstall the softmod after a firmware upgrade/downgrade?

🅰️ If the firmware upgrade was for the Disco only (and not for Skycontroller 2), you can simply run the following steps

  • Turn on your Disco and connect your PC's Wi-Fi to the Disco (e.g. DISCO-123456).
  • On Disco firmware 1.7.0 and newer: Double press the Disco's power button to enable the telnet server.
  • Open a Command Prompt (Windows)/Terminal (macOS/Linux) and Copy/Paste the following commands manually.
    • telnet
    • mount -o remount,rw /
    • ln -s /data/ftp/uavpal/conf/70-huawei-e3372.rules /lib/udev/rules.d/70-huawei-e3372.rules
    • reboot

⚠️ Note: all configuration files on the Disco will be retained.

If you upgraded/downgraded Skycontroller 2's firmware, or if the above steps did not work, you should do a full reinstallation according to the Installation Instructions. Have a look at this FAQ entry on the steps that can be skipped during the reinstallation.

How do I update the softmod to the latest version? / How do I reinstall the softmod?

🅰️ Basically, you need follow the Installation Instructions again. The download link in the instructions is always the latest stable release. You do not need to uninstall/run the Removal steps.
If the softmod was/is already working fine, you can skip the following steps:

  • Creation of Glympse, Pushbullet and ZeroTier accounts
  • Authorization and setting of Ethernet Bridging in the ZeroTier Web UI (as long as the ZeroTier Network ID has not changed).

⚠️ Note: make sure you set the configuration files in the downloaded and extracted .zip archive again according to your preference.

Why should I setup Glympse as independent location tracking software, when I can see the Disco's location in FreeFlight Pro?

🅰️ Glympse is a great fail-safe feature and gives you detailed information of the Disco's whereabouts if

  • the FreeFlight Pro App crashes or loses connection and is unable recover
  • the mobile hotspot crashes, runs out of battery or runs out of data
  • the phone/tablet running FreeFlight Pro runs out of battery or crashes
  • Skycontroller 2 runs out of battery

Additionally, Glympse shows more 4G/LTE relevant data than FreeFlight Pro: the name label (e.g. DISCO-123456) is followed by detailed telemetry data, e.g. Sig:4G/70% Alt:45m Bat:86%/12.09V Ltn:28ms [D]

  • Sig:4G/70% - the mobile signal of the drone's modem. 3G vs. 4G and the signal strength in percentage, derived from the RSSI dBm
  • Alt:45m - the current altitude in meters, relative to the take-off point
  • Bat:86%/12.09V - battery capacity in percentage and voltage (important for some of the Li-Ion battery mods)
  • Ltn:28ms - latency between the controller and the drone (shown in Wi-Fi and 4G mode)
  • [D] / [R] - indication whether the ZeroTier connection is [D] direct (low latency, full throughput) or [R] relayed via ZeroTier's cloud infrastructure (higher latency, limited throughput)

How do I install telnet on my PC as it seems not to be available?

🅰️ Please find the instructions depending on the Operating System you are using below.

  • Windows: follow these simple steps.
  • macOS: telnet is no longer available on newer version of Apple's macOS. You have the following three options:
    • download the binary, run chmod +x telnet and start it with ./telnet
    • try nc 23 instead of telnet
    • install telnet via Homebrew (Instructions)

Is it possible to uninstall/remove the softmod?

🅰️ Please see Wiki article Removing the softmod

Can I just reinstall Disco4G? Will anything be overriden?

🅰️ You can simply follow then instructions to reinstall the softmod. There are good reasons for reinstalling, we are constantly improving Disco4G, so you might want to reinstall the latest version. Don't forget to set your preferences in the conf files again after downloading the latest version from GitHub, otherwise the existing config files on the Disco and Skycontroller 2 will get overriden with the example files.

⚠️ Note: A reinstallation does not require re-authentication in the ZeroTier Web interface (unless the Network ID has changed in your config file).

I just want to make a change to a config file (e.g. phone number to receive the Glympse link via SMS) - do I need to reinstall everything?

🅰️ No, not required. You can change the respective config file on your PC using a text editor and upload via ftp directly into /uavpal/conf/ on your Disco.
However, if the config file you want to change is on Skycontroller 2 (e.g. Wi-Fi passphrase), it gets a bit trickier. Reinstall is the easiest option unless you are a Unix/Linux guru.

Under what circumstances does ZeroTier create a direct connection (low latency, full throughput) between the Disco and Skycontroller 2, and when does it use an Internet relay (higher latency, limited throughput)?

🅰️ The following scenarios are possible:

  • 2 SIMs same carrier - internal connections allowed - direct
  • 2 SIMs same carrier - internal connections blocked, NAT traversal might be possible - mostly direct, some relayed
  • 2 SIMs same or different carrier, at least one SIM with public IP - direct
  • 2 SIM different carriers, two symmetric NATs cannot be traversed - relayed

Check out our list of Known Working Mobile Carriers and Settings, to see if ZeroTier is able to get a Direct or Relayed connection per carrier.
Glympse indicates whether the current connection is direct or relayed ([D] or [R]).

Can I use the softmod without zerotier, as I don't want to rely on third-party infrastructure?

🅰️ You can try tinc instead, however we do not provide the instructions for it.
Or you can set-up your own zerotier relay server (called "moon")

Can I participate in beta testing? / How can I try the latest untested version of the softmod?

🅰️ Download the beta archive instead, the rest is according to the Installation Instructions. In addition to the existing Disclaimer, the beta version might not have been tested. It is strongly recommended to do some ground tests before flying.

Feedback via our Slack Workspace (#dev channel)


My 4G/LTE connection is slow or unstable: the video stream is choppy and/or delayed and I get disconnected regularily

🅰️ Check the following possibilities:

  • Your carrier's coverage might be bad in the area where you are trying to fly, you can use CellMapper or OpenSignal to check for 4G/LTE coverage.
  • It is highly recommended to use both SIM cards from the same carrier for higher performance and lower latency. Also check that you are using the same APN on the Disco and your mobile tethering device (if possible).
  • ZeroTier might be relaying the connection via public Internet, see this FAQ entry for more information.
  • Make sure your mobile tethering device as well as the Disco's modem have a 4G (and not a 3G) connection, see also Huawei E3372 LEDs.
  • Using a single device for the mobile hotspot and FreeFlight Pro can have a performance impact if the device is not powerful enough. Although it's possible, we recommend to use two separate devices, one as mobile hotspot with Glympse and the other one running FreeFlight Pro which is connected to SkyController 2 via USB cable.
  • Some carriers impose a bandwidth cap to tethering data (e.g. T-Mobile USA). Make sure your carrier unlocks the full speed.
  • Run the following two speed tests to confirm there is sufficient bandwidth available:
    1. Plug the modem into a PC and use a browser to run a speed test, e.g. (ensure the PC has all other LAN/Wi-Fi interfaces disabled)
    2. Use a PC and connect it via Wi-Fi to your mobile tethering device, use a browser to run a speed test, e.g. (ensure the PC has all other LAN/Wi-Fi interfaces disabled)
      It's important not to use an App on your mobile tethering device to conduct the second speed test. It will not reveal any carrier imposed bandwidth cap on tethering data.
  • If the connection is lost and does not recovered at all, confirm that you have sufficient data balance available on both SIM cards.
  • If your recording quality is set to 720p in FreeFlight Pro, the video stream will require more bandwidth as it's 720p as well. We recommend to record at 1080p, so the video stream quality will implicitly be set to 480p, which is slightly lower quality but also requires less data and bandwidth. More info here.

Why does my modem's LED keeps flashing when connected to the Disco?

🅰️ Your modem is not connected to the Internet, you should check the following:

  • Has the softmod been installed without any error? If not, reinstall the softmod
  • Have you recently upgraded the Disco's firmware, see "Do I need to reinstall the softmod after a firmware upgrade/downgrade?"
  • Are you using a supported modem?
  • Is the USB cable used to connect the modem to CHUCK just a power-only cable without data wires? This will not work, you need a proper USB OTG cable.
  • Is the SIM card inserted properly?
  • Is the SIM PIN code disabled? This is required for the softmod to work!
  • Does the modem work when plugged into a PC?
  • If you have upgraded from an earlier version of the softmod, please ensure that you set the apn config file correctly, it was not required with older versions (on Hi-Link modems).

Double pressing the Settings button on Skycontroller 2 does not (always) trigger the 4G/LTE mode (LED does not start to flash in magenta), anything wrong?

🅰️ Give it a firm press and wait for about a second before pressing again.
If it still does not work and never worked before, repeat the installation steps.

Why does the installer script return file not found?

🅰️ The files have been transferred in ASCII instead of Binary mode. Please start the Installation over again and make sure the FTP transfer mode is set to Binary prior to transferring the files.

Why does Skycontroller 2's LED keeps flashing blue for minutes until it switches back into Wi-Fi mode (green LED)?

🅰️ This is almost exclusively related to ZeroTier not being able to create a connection between your Skycontroller 2 and Disco. Please login to the ZeroTier Web UI:, and check the following under the tab "Networks":

  • Two members need to be listed (Disco and Skycontroller 2) - both should indicate status "Online" while Skycontroller 2's LED is flashing blue.
  • Both need to be authorized (checkbox "Auth?" should be set).
  • Both need to have "Allow Ethernet Bridging" enabled (click the wrench icon).

If you have accidentally removed a member in the ZeroTier Web UI, it will be blocked from joining. You will need to remove and then reinstall the softmod again, so that the Skycontroller 2 and the Disco gets added as new members again (of the same Network ID).

I did not receive the SMS with the Glympse link to track my Disco's location, anything I can do?

🅰️ Make sure the USB modem is successfully connected (blue or cyan solid LED on the modem)

  • Some SIMs are "data-only" and don't allow you to send SMS. This is a restriction imposed by your mobile network operator.
  • Some users have reported it worked when omitting the international prefix or just the "+" in front of the number in the conf/phonenumber file.
  • The phone number in conf/phonenumber should be the device where you want to receive the SMS with the link (and not the Disco's SIM phone number itself).

    👉 As alternative to SMS, you can also use Push Notifications to receive the Glympse link. Have a look at the Installation Guide.

Why does the Setting dialog appears quickly on FreeFlight Pro when I double press Settings on Skycontroller 2?

🅰️ The Settings button will always open the Dialog when flight mode (full-screen video) in FreeFlight Pro. We have chosen a double press for the switch-over between 4G/LTE and Wi-fi for two reasons: 1. An unintentional press on the button will not trigger the switch-over, and 2. As the Settings dialog cannot be suppressed, a double press will at least close the dialog again.

Skycontroller 2 is trying to connect to a tethering device such as an iPhone, it keeps flashing magenta for some time and is then falling back to green (Wi-Fi mode).


  • Make sure you set the config files ssid and wpa correctly.
  • For iOS: the curly apostrophe (single quote sign) in the Hotspot's name can be an issue, e.g. "Name’s iPhone". Quick fix: remove any special characters (e.g. "My iPhone"). This can be done in Settings → General → About → Name. If you want to use the straight apostrophe sign (e.g. "Name's iPhone") instead, you need to rename it in iTunes as the iOS keyboard does not offer straight apostrophes.
  • For iOS: if Personal Hotspot was activated for a long time, it stops broadcasting itself. This is a known iOS issue. You might need to disable and re-enable Personal Hotspot, or even restart your iOS device.

How can I debug issues on the Disco?

🅰️ You can connect your PC via Wi-Fi to the Disco and telnet into
On Disco firmware 1.7.0 and newer: Double press the Disco's power button first to enable the telnet server.
By running the command ulogcat | grep uavpal you see the log messages created by the softmod.

All logs on the Disco are only stored in memory and are therefore lost after the Disco is shutdown. To persist the kernel and user logs on the internal storage: create an empty file /data/ftp/uavpal/conf/debug, the softmod will then write all logs into /data/ftp/internal_000/Debug/ulog_debug_{date/time}.log, these log files can easily be retrieved via ftp (in /Debug) as well.

How can I debug issues on Skycontroller 2?

🅰️ a) Make sure your Skycontroller 2 is connected to the Disco via Wi-Fi (green Power LED on the controller). You can first connect to the Disco (see above) using telnet and run /data/ftp/uavpal/bin/ to hop on to Skycontroller 2.
b) You can directly connect from your PC to Skycontroller 2 using a USB Ethernet adapter on Skycontroller 2 connected via Ethernet to your PC. You need the tool adb which is freely available for all major OS platforms. The Apple USB Ethernet Adapter (MC704ZM/A) is known to work.
By running the command ulogcat | grep uavpal you see the log messages created by the softmod.