Build: 3-inch 2S Ultralight Drone using Flywoo GOKU F405 HD 1-2S 12A AIO V2 FC

by Oscar
3inch Toothpick Ultralight Fpv Drone Build 2s Walksnail 1s Vtx

In this post, I will share my 3″ Toothpick build (a sub-100g micro FPV drone) using the latest Flywoo GOKU F405 1-2S 12A AIO FC. This quad will be using the Walksnail FPV system and powered by 2S batteries. I will also share my thoughts and experience from using the GOKU F405 12A AIO FC. Consider this a mini-review.

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Learn more about flight controllers in my buyer’s guide:

My Experience with the Flywoo GOKU F405 1-2S 12A AIO FC

Product Page:

It comes with the following accessories.

Flywoo Goku F405 Hd 1 2s 12a Aio V2 Fc Unbox Accessories

Why I really like the Flywoo GOKU 1-2S 12A AIO FC:

  • Built-in ExpressLRS 2.4GHz receiver (UART), making it a compact solution.
  • Offers 6 UARTs! Normally, whoop/toothpick style FCs only give you 2 UARTs, which is very limiting. With this many UARTs, you can literally use it on any build.
  • Multiple 4.5V pads, which I use for powering the receiver and GPS. This allows you to power these devices through USB without the need to plug in the battery, to avoid overheating VTX.
  • Has 8MB of flash memory for Blackbox logging! This is useful for tuning your quad. Most other 25.5×25.5mm FCs simply do not have this feature.
  • SDA and SCL (i2c) connections allow you to connect a compass. Again, this feature is usually missing in this type of board!
  • Onboard barometer!
  • Offers both MPU6000 and ICM42688-P gyros.
  • Has a 9V 2A BEC for powering your VTX!
  • Supports iNAV!
  • ESC’s have been flashed with Bluejay 0.19 24KHz in factory.

One of the biggest benefit of this FC would have to be the 9V electronic switch:

By controlling the USER2 switch, you can turn the the 9V output ON and OFF. This allows you to temporarily shut down the VTX if you are powering it with the 9V BEC, to prevent overheating on the bench. Here’s how to set it up:

  1. Connect the Flight Controller:
    • Connect the flight controller to the Betaflight Configurator.
    • Switch to the “Modes” interface.
  2. Configure USER2:
    • Scroll down to find USER2.
    • Select “Add Range.”
    • Move the joystick switch on the remote controller that you wish to configure.
    • Save the settings.
  3. Activate USER2:
    • Activate USER2 to control the 9V power supply as needed.

What I don’t like about this FC:

  • The biggest downside of this FC is probably the absence of the OSD chip for analog (AT7456E). The new V2 is designed for HD systems, such as Walksnail, HDZero, and DJI, which don’t need this chip to display OSD in the goggles like analog does. I guess analog is becoming less popular, and this change lowers the cost of production as well. You can still use it with analog if you really want to, but Betaflight OSD won’t work.
  • I wish there was an additional version with a horizontal USB port. This would support a wider range of frames and make it more versatile.

Overall, I think the GOKU F405 1-2S 12A AIO FC is one of the best flight controller boards for 1S or 2S toothpicks and whoops, especially for those digital FPV builds like Walksnail, DJI, and HDZero with its 9V BEC.

Here’s a side-by-side comparison between the V1 and V2 of the GOKU 12A AIO FC.

Flywoo Goku F405 Hd 1 2s 12a Aio V2 Fc Compare V1 Versatile

Some close-ups of the flight controller, top and bottom.

Flywoo Goku F405 Hd 1 2s 12a Aio V2 Fc Front

Flywoo Goku F405 Hd 1 2s 12a Aio V2 Fc Back


  • BF Flight Controller Firmware: FLYWOOF405S_AIO
  • INAV Firmware: FLYWOOF405PRO
  • MCU: STM32F405BGA
  • BEC: 5V 2A / 9V 2A
  • Flash: 8MB
  • LED: 2 × WS2812
  • Barometer: DPS310 / SPL06
  • Gyro: ICM42688P / MPU6000
  • Motor: M1-M4 OUTPUT I2C: SCL/SDA
  • UARTs: 1, 2, 3, 4, 5, 6
  • Connector: Type-C
  • OSD: No
  • Hole: 25.5 × 25.5-3mm
  • Size: 30 × 30mm
  • Weight: 4.9g

Onboard 4-in-1 ESC

  • Built-in 1S/2S 12A BL_S 4-in-1 ESC Supports Oneshot125, Oneshot42, Multishot, Dshot150, Dshot300, Dshot600
  • Input Voltage: 1-2S Lipo
  • Firmware: BLHELI_S Bluejay 0.19 24KHz
  • Firmware Version: Z_H_30_REV16.7

ELRS 2.4G RX (Optional)

  • ESP8285 MCU
  • SX1280IMLTRT RF Module
  • Frequency Range: 2400 MHz to 2500 MHz
  • Maximum Receive Refresh Rate: 500Hz
  • Minimum Receiver Refresh Rate: 25Hz
  • Serial: UART 1
  • Firmware: Flywoo EL24P 2400 RX
  • Version: 3.X.X
Specification GOKU F405 HD 1-2S ELRS AIO V2 GOKU F405 1-2S 12A AIO ELRS
BEC 5V 2A & 9V 2A 5V 2A
Flash 8MB 8MB
Onboard LED 2*WS2812 2*WS2812
Barometer DPS310/SPL06 DPS310/SPL06
Gyro ICM42688P / MPU6000 ICM42688P / MPU6000
i2c SCL/SDA Yes Yes
UARTs 1, 2, 3, 4, 5, 6 1, 2, 3, 4, 5, 6
Connector USB Type-C Micro USB
Analog OSD No Yes (AT7456E)
Mounting 25.5*25.5mm 25.5*25.5mm
Size 30*30mm 30*30mm
Weight 4.9g 4.1g

Here’s the pinout diagram.

Flywoo Goku F405 Hd 1 2s 12a Aio V2 Fc Manual Pinout

3″ 2S Walksnail Toothpick Build

Parts list:

Currently, the lightest frame I could find is the Babytooth, but it’s almost never in stock (I’m also quite surprised it’s still not been cloned at this point). Also, it’s not designed for FCs with vertical USB ports, which are the most common type of FC. There aren’t many whoop-style FCs available with horizontal USB ports, so I normally just flip the board over and re-configure the board alignment in Betaflight. I am getting some new 3″ toothpick frames to try out in the next couple of weeks, hopefully will find a good replacement.

First, mount the motors.

3inch Toothpick Ultralight Fpv Drone Build 2s Walksnail 1s Vtx T Motor 1103

Then, install the Walksnail 1S VTX to the frame and solder it to the FC. I am powering it from the 5V pad on the FC as the 1S VTX only supports 3.3V to 5V input.

3inch Toothpick Ultralight Fpv Drone Build 2s Walksnail 1s Vtx Connect Flywoo F405 1 2s 12a Aio Fc

I also soldered a capacitor to the XT30 power pads, which come with the FC. I am using BetaFPV’s micro lite canopy designed for tiny whoops, but it works fantastic on this build. It has just enough room to house the USB port. However, I do need to remove the canopy if I want to connect the FC to Betaflight, which is slightly annoying.

3inch Toothpick Ultralight Fpv Drone Build 2s Walksnail 1s Vtx Electronics Canopy

The build weighs only 59g excluding the battery, and with a 2S 550mAh battery, it weighs only 88g. I can still make it lighter by:

  • Shortening the motor wires and XT30 pigtail.
  • Using fewer zip ties.
  • Not using screws for mounting propellers (I only have props with 2mm holes, and those motors have 1.5mm shafts, so I have to use screws for now).
  • Using a lighter canopy.
  • Using a lighter battery mount.

3inch Toothpick Ultralight Fpv Drone Build 2s Walksnail 1s Vtx Weight Sub100 Sub250

Let me know if you have any questions in the comments.

3inch Toothpick Ultralight Fpv Drone Build 2s Walksnail 1s Vtx

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Td 29th June 2024 - 1:32 am

I love this AIO but the one issue is the VTX Switch, did you have any issues? it would seem that when bidirectional dshot is enabled it cuts it off every 10 seconds or so, no matter if the switch is on or off.

Oscar 1st July 2024 - 4:19 pm

I haven’t tried this feature since I’m powering the VTX from 5V, not 9V. Can you try extending the range of User2 from 0 to 100%? If that fixes it, that would suggest an issue on the radio side. But if the same still happens, try removing User2 from the Modes tab and see if that works? If same problem, that would be an issue in Betaflight. Of course, make sure you backup Betaflight first before doing these.

Steve 24th June 2024 - 10:35 am

This looks great – I have the parts ordered and this will be my first build. Is there anything special to consider when setting it up in betaflight? I am learning so much from your site, thank you.

aaron 20th June 2024 - 6:30 pm

would you mind sharing your pids for this 2S build?

Oscar 25th June 2024 - 4:32 pm

Yes I am still working on that. Once it’s ready I will share it.

bar1 20th June 2024 - 5:01 pm

This inspired me, for a first build, and I have the parts en route!

can I just use the connector to connect the 1s walksnail system or is it only for DJI?
It would be nice to use with GPS, and maybe even a buzzer but I suppose I am going to need to find space for those….

More questions to come….l-p thank you!

Oscar 20th June 2024 - 5:05 pm

You can absolutely use the connector, just remove the SBUS wire which is not needed for Walksnail. I didn’t use the connector because the 1S VTX does not take 9V.
And yes, this FC can do GPS as well as buzzer, just need to figure out how to mount them.

Tomás A 15th June 2024 - 6:50 pm

If you would compare this 2S all in one set up with a 4S, would the 4S be louder but have longer range?

Oscar 15th June 2024 - 11:22 pm

Louder? Yes, because it’s heavier and motors have to work harder.
Longer range? Depends on battery size, so not necessary.