Wltoys V303 firmware and driver

Wltoys V303 driver and YS-S4 firmware download page

The Wltoys V303 using the Zero UAV flight controller is a very versatile and easy to fly quadcopter. If you have any prior experience with mini quadcopters, I think you will be able to pilot the V303 without any problems at all.

Through the USB port the owners can update the V303 Seeker firmware but first they need to install the V303 driver. The PL2303 USB-to-Serial driver is available for most common operating systems (Windows, OS X and Linux).

Upgrading the YS-S4 flight controller’s firmware can improve the control sensitivity and the flying stability.

Upgrading the Wltoys V303’s firmware is a very risky process, it can brick your quadcopter, proceed only at your own risk!

Wltoys V303 PC connection steps:

  • Download and install the latest V303 USB driver, this quadcopter uses the Prolific PL2303 USB-to-Serial bridge;
  • Download and read the PL2303 users manual;
  • Download and unpack the PC-GCSsoftware-S4V2 tool;
  • Download and read the Zero Tech YS-S4 multi-rotor autopilot users manual;
  • Download and read the Wltoys V303 users manual;
  • Turn on the remote controller;
  • Load the battery in to the quadcopter;
  • Wait until the LED lights flashes red / green;
  • Connect the Wltoys V303 to your PC through the USB cable;
  • Run the S4-GCS-USB tool and open USB (the tool works only under Windows).

Now you are ready to adjust your Wltoys V303 flight parameters and install the latest firmware.

Wltoys V303 firmware and driver downloads:

V303 Seeker driver download (for Windows, OS X and Linux)

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PL2303 user manual download

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YS-S4 flight controller user manual download

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Download the PC-GCSsoftware-S4V2 V303 software

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Download the latest 4v2-Standard-20140902-v068-abroad V303 firmware

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s4v2-Standard-20140902-v068-abroad firmware release notes:

  • increase flying stability;
  • increase sensitivity of controlling;
  • eliminating drafting when flying indoor;
  • modify the LED indications;
  • adds magnetic compass protection (if the magnetic compass has error, the motors can not be armed).

Happy fly with your Wltoys V303 Seeker quadcopter!


  1. I have downloaded driver and software and have installed new mainboard on v303 but will not allow me to open usb. I get ! yellow triangle message each time I try to open usb no matter which way I hook up to computer. Any help please. running windows 7 32 bit

  2. What is wrong with my WL V303 when it flashes red then green and back to flashing red again. Tried the calibration above and can only get to green horizontal when I go to vertical the light stays off no matter where I put it . unplug and back to flashing red.
    Can you help me?

  3. ESC red light control system was broken down and I plan to replace it with a new one. But i dont know whether or not i have to reset the system again based on config V303 on PC or do anything else after i assembly it successful!

    Pls help me.

  4. My V303 does not have GPS, if I update firmware, will it lock my motors, as I see this and wonder is that by default, or an option you chose:

    “adds magnetic compass protection (if the magnetic compass has error, the motors can not be armed).”

    THANKS in advance

  5. Bjornar:
    Assuming you have the correct rotation on the motors (like rotations are opposite diagonally), double check that the prop rotation marks are correct for the motors. The marks are often not the easiest to see. If it is a new motor with the same problem, a bad esc might be a problem. Let us know what you find.

  6. I have a problem with my v303 quad.
    Replaced with new motor left behind. Because it did not run as it should, but the problem was not solved.
    The quadcopter does not rise, but just tilts over, towards this engine.
    What could be wrong?

  7. Had the same issue, solid red led and tx not working. fixed by flashing 075 firmware. grab the usb drivers from this site, the pc gcs software s4v2 ( with gimbal support) from zerouav.com under the support tab ( actually works better than anything else i found) and the 075 or 057 firmware from atoc2tech.fr/blog/v303-firmware-mise-a-jour near the bottom of the page flash as normal, dont forget to put your toggles in the right position.

    The 075 firmware seems to be the same as the 068, but it works.

    Hope this helps

  8. To whom it may concern,

    We have recently acquired a Seeker V303 and it worked perfectly. However, during our last trial the device took off normally until all of a sudden it freaked-out and we totally lost its control, even though the quadcopter was within reach/range of the remote. The quadcopter was not responding to the remote and subsequently it crashed on its own.
    Before we lost its control we noticed that the quad copter was displaying a yellow-flashing light, something which we have not seen during previous flights.

    Following the crash we tried to calibrate the magnetic compass, as instructed in the instruction book. However, we didn’t succeed to calibrate the device as the operation failed every time we tried. Now, when switched on, the V303 is only flashing yellow and red lights and the motors are not triggering when armed.

    Could you please guide us for a possible solution in this regard?

    I thank you in anticipation.


    • Here is an excerpt from the YS-S4 user manual (the FC manufacturer) of the V303, which describes the calibration process somewhat differently from the V303 manual. I had a similar issue to you in that I got “stuck” in the calibration mode. The key for me was that I had to try several times but eventually was able to rotate the V303 during horizontal calibration without the light going out in the process. When it did go out out I restarted the calibration process again from the top. (This seemed key to a successful outcome.) It took me at least a half dozen attempts before I got through it. Turn it as slowly as needed to keep the light on! I continued with the vertical calibration with the nose down rotating it counterclockwise again being careful to keep the light on. I actually got a red light during the vertical calibration but had a successful outcome. It is a great feeling to see the green and red blinking lights again. Hope this helps you and any others stuck in Seeker Calibration Hell!

      Step 2
      Rotate the multicopter counter clockwise( or clockwise) three times. ENSURE that the GREEN LED remains ON
      during this procedure. If it turns OFF, it means the aircraft is not horizontal. Adjust the position until the GREEN
      LED is back ON and continue with the rotation and put the multicopter level again.

      Step 3
      Flip CH5 switch three times(1 > 2 > 1 > 2 > 1 > 2 > 1) and the LED turns off. You have entered Vertical Calibration.
      Hold the multicopter nose down and the LED turns green.
      Rotate the multicopter 3 times counter clockwise as shown below, always keeping the aircraft nose down. Ensure
      the GREEN LED remains ON during the turn. If the LED turns OFF, adjust the attitude of the multicopter until the
      GREEN LED is back ON and continue with the rotation and put the multicopter level again when finished the
      rotation. The LED turns off.

    • Hello, if you could not solve the problem to start the engines. I commented that with the software driver S4 flight must put the same default values and calibrate the control knob. Save the changes and fly again. With respect to the calibration you have achieved make it, because I have not been able.

  9. Do the magnetic compass adjustment if your motors won’t arm. It is tricky.
    If you do it wrong you get constant yellow red flashing light (rapid). Mine flies perfectly. 1 month old and have never had to touch the trims.

  10. I was looking for an instruction manual to the v303 seeker with the brushless gimbal. I want to know how to install.
    Does this exist?

  11. Just got my v303 (almost 90 days later). turned transmitter on works. turned seeker on it binds. worked sticks down then outward; nothing. The motors wont startup. am i doing something wrong or the motors not working? Oh yeah i get home switch lights and compass lights. do i need a new transmitter or am doing something wrong?

  12. why dont you guys return that shit? I’ve returned 2 of these pieces of chinese trash now… third V303 quad on the way. hopefully it isn’t a piece of shit too

    • not touch the program, original is working well
      never actualeces data. (V303 has a special program.)
      no toques la programación .como viene funciona bien
      no actualeces los datos .( seeker v303 tiene un programa especial .)

  13. Attempted firmware update now status light stays solid red, motors won’t arm. Though that NEW flight controller would solve the problem but after swapping out with brand new YS-4S FC I still have exact same problem! HELP!!!!

  14. I followed these instructions and although it said it flashed successfully the status light stayed red and the controller no longer worked.

    I tried re-flashing but same issue.

    After reflashing a copy of the 057 firmware it was working again.

  15. Paul
    February 8, 2015 – 18:46:26
    Hey just have a question.
    I did the firmware upgrade and everything seemed like is working but it’s not conecting to the controller. can you please help me.

    Hey, i have the same problem.
    Seeker show green/green light, but the motors don’t start when i try in the controller.
    NEED HELP. only fly 1 time :(

  16. Hey just have a question.
    I did the firmware upgrade and everything seemed like is working but it’s not conecting to the controller. can you please help me.

  17. I don’t have Windows PC but I have Mac. Any option I have to use the S4-GCS-USB tool since it says above that I can only use it on Windows.

    I noticed as well that USB driver works on OS X. How do I use on Mac if I cannot use the S4-GCS-USB tool?



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