Open-Source Firmware for a Mini Quadrotor

Since you’re going to have to be flying your “drones” indoors anyway in the USA, at least in the US Capitol region, you might as well celebrate the one freedom you still have — the freedom to re-flash the firmware!

The Eachine H8 is a typical-looking mini-quadcopter of the kind that sell for under $20. Inside, the whole show is powered by an ARM Cortex-M3 processor, with the programming pins easily visible. Who could resist? [garagedrone] takes you through a step-by-step guide to re-flashing the device with a custom firmware to enable acrobatics, or simply to tweak the throttle-to-engine-speed mapping for the quad. We had no idea folks were doing this.

Spoiler alert: re-flashing the firmware is trivial. Hook up an ARM SWD programmer (like the ST-Link V2) and you’re done. Wow. All you need is firmware.

The firmware comes from [silverxxx], and he’s written all about it on the forum at He’s even got the code up on GitHub if you’re interested in taking a peek. It looks like it’d be fun to start playing around with the control algorithms. Next step, Skynet!

Reading the forum post, it looks like you’ll have to be a little careful to get the right model quad, so look before you leap. But for the price, you can also afford to mess up once. Heck, at that price you could throw away the motors and you’d have a tricked-out ARM dev kit.

And if you insist on hacking everything, you can probably re-purpose a wireless mouse controller to control the thing. Write your own code for the controller and you’ve got an end-to-end open firmware quadcopter for a pittance.

13 thoughts on “Open-Source Firmware for a Mini Quadrotor

  1. I’m from Germany after reading this I looked into my copters, I got for cheap and there are the same Chips built in so it should be possible too with:
    The Zoopa Q 165
    Spirit X005

    Looking over this in a hurry its looks basically like the same design only the first has 6 and the second 4 Channels.

    I have to look into this later … nagging Master Thesis and stuff. Maybe someone with the same models wants to look into this … have fun hacking …

  2. Doesn’t the ARM Cortex M3 IP come with firmware protection? If so, are the Chinese manufacturers of these cheap drone clones jus not using it? (That would be very un-Chinese-like.)

    1. Unless they’ve sprung for a mask ROM, these chips are generally execute only. The firmware protection features on these chips stops (sometimes) people like us from reading the ROM contents verbatim back out of the device (to dump the firmware), but we are allowed to reprogram the flash ROM with our own content, on the proviso that the flash must first be erased.

    2. It’s just blowing away the firmware that’s already on there. Most chips will let you do a full reset/reflash, they note that readback is locked out so this is a one-way process. Also, I think the actual chip is one of the STM32 clones that’s come out recently. Very Chinese.

  3. Hint: the original controller is awful, but you can use these from Bayangtoys copter, like the X7 or X9. Or, even better, modify a Devo 7E with Deviation firmware and a NRF24L01.

    1. thanks for the tip – I’m new to quads, but I followed your advice and bought the 7e, modded it with the nrf24l01 and a7105 (for hubsan use) and now all 4 of my quads, of various brands and sizes are all controllable. would never have known about the 7e without your post, so cheers, man! and the h8-mini is one hell of a fun quad!

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