Unbricking a SkyViper transmitter

A bug has been found in the SkyViper transmitter firmware which can cause the transmitter to “brick”. When it happens the transmitter will power on with only the red LED showing and no sound. This bug has been reported here:


(and perhaps in other places)

we will be releasing an updated firmware soon that will prevent the problem from happening, but in the meanwhile I am posting instructions here on how to fix your transmitter.

Fixing the Issue

To test quickly if your transmitter can be fixed you should power it on while holding the left shoulder button (the one marked with a video camera) and also holding the left stick fully down (as though doing zero throttle). If the transmitter starts up and does its startup tones then the unbricking procedure listed below will work. This combination of buttons puts the transmitter into factory test mode with factory test channel 3.

It is a bit of a complex procedure, so follow the steps carefully.

The fix is as follows:

It will look like this:

  • Now reboot your SkyViper (pull the battery plug out and put it back in)
  • While holding in the the left shoulder button (the video button) on the transmitter and holding the left stick fully down power on the transmitter

At this point the transmitter will power on and will connect to your SkyViper. Now you should leave both the transmitter and SkyViper powered on for one full minute.

After one minute go back to the ‘Radio’ section of the parameters in the web UI and change BRD_RADIO_TESTCH to ‘Disabled’.

Then power off both your SkyViper and your transmitter and power them back on again. Your SkyViper should now function normally.


There was a bug in the transmitter firmware related to high WiFi channel numbers that tries to avoid conflicts between RC transmitter channels and WiFi channels. If the WiFi channel number was set to 11 or higher than it would fail to complete the code that selects a channel for the transmitter on boot. Forcing a fixed channel with factory test mode allows us to fix the problem.


Love it. Excellent explanation. Thanks for keeping at it.

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Thanks Tridge. Let us know when the new firmware is ready to push.

Is there way to use SkyViper whitout transmitter? I travel with plane and they took transmitter cause of batteries. I use only autopilot anyway.

With Mission Planner you can fly with a connected game controller, but there are some potential gotchas there. I’ve done it inside my house for fun.

You can also just connect Mission Planner (and others I’m sure) to the SV over MAVLink and command it through the Actions menu. It works, and I’ve done it, but you better be watching it!

You cannot “Arm” in Auto mode, so you’ll need to ARM it in Loiter (after GPS lock) and use the game controller to take off and hover, then switch to “Auto” mode to fly the mission.

Using the game controller you’ll need to hold the throttle down to arm, because the throttle has to be “0” to pass pre-arm checks (unless you disable, but not recommended)

This process did not help for me. The transmitter is stuck on the red light while the green GPS light is flickering and making a clicking sound… This sucks as I just bought it from toys r us and all sales are final… @tridge can you help?

wow…sounds like a totally different issue. a clicking sound? i don’t think there is anything in the transmitter to click…unless the speaker is crackling. Is there any chance that the skyviper sees the transmitter, so you could push a firmware update to it?

did it do this the first time you turned it on, or after an update?

connect your PC to the skyviper wifi, then in a web browser go to, click on the status link, then transmitter status. see if the skyviper sees the transmitter connected…

So it actually sounds like the startup sound starts then immediately stops creating a sort of clicking sound. Sky viper does not see the transmitter.

You’ve probably already though of this, but low TX battery could cause that.
Otherwise most likely a hw fault

If HW fault you might be able to get skyrocket to replace the transmitter…if they have any available.