Introduction: Transform a Cheap RC Transmitter With Custom Firmware

Picture of Transform a Cheap RC Transmitter With Custom Firmware

The Turnigy 9x is a cheap Chinese radio transmitter widely sold by hobby king and other retailers under a variety of names. This is a computerized radio transmitter and is already a great deal for the price ($53 currently) and pretty capable if you can figure out how to use the stock firmware. The microcontroller running the show is a common ATMEGA64 type and is not code protected, so several groups of dedicated hobbyists have completely rewritten their own firmware versions that vastly improve the radio and are open source to boot. This instructable will show the steps required to modify your radio and reflash it with the firmware of your choice. 

Step 1: Tools and Materials

Picture of Tools and Materials

For this instructable I used:
an old IDE cable,
some other bits of wire,
2x6 pin header,
hot glue.

you will also need:
a soldering iron, 
hot glue gun,
small saw,
wire cutters/strippers,
an AVR ICSP programmer, I used a USBasp
a PC.

Step 2: Open It Up!

Picture of Open It Up!

First thing to do is to remove the battery door and the battery pack within. next unscrew the six screws on the back of the unit and gently lift the back of the case. unplug the long connector in the middle holding the two halves together. set the back half aside.

Step 3: Ribbon Cable

Picture of Ribbon Cable

Time to tear apart your IDE cable. Remove six conductors from the ribbon on the side with the red stripe. These will be used to connect your programming port to the appropriate pads on the main board.  Separate the wires and strip them. If you have a 2x3 female pin header plug you can use that, otherwise use a thin saw to cut a piece of the connector that is three long. carefully sand the edges smooth. take your mini-ribbon cable and bend every other wire the same direction, so that the wires line up with the plugs on the connector section. solder them together. 

Step 4: Solder to the Main Board

Picture of Solder to the Main Board

next, carefully place your iron on each of the pads shown below and apply a small amount of solder to them. separate and tin the ribbon cable wires, and solder them to each pad so that the 6-pin header matches that in the ICSP header diagram. once connected, apply some hot glue to the ribbon cable to act as a strain relief and hot glue the ribbon to the board. before cutting the case of the radio to install the header in its final location make sure that you will be able to close the case once its installed. I was a little careless and ended up having to notch the other side of the case slightly to make room.

Step 5: Optional: Adjust Stick Spring Tension

Picture of Optional: Adjust Stick Spring Tension

the sticks on this radio seem a little loose from the factory, so I adjusted the spring tension while I had the radio on. there are three screws that adjust the springs and a fourth to adjust the stiffness of the throttle stick. these screws are highlighted in the below pictures, turn right for more resistance. 

Step 6: Flash Firmware

Picture of Flash Firmware

reassemble everything, and fire up the PC. I use a software program called EEPE created by the same people responsible for the ER9X firmware I am using. this is basically a front end GUI for AVR dude, and it also allows you to back up and edit EEPROM data from the MCU. Information about the settings for each model profile in the radio is stored here, so the ability to edit it or share the info with others on the internet is useful.  install EEPE and  go to burn-> configure. select your programmer from the programmers drop down, and port if applicable (not necessary for usbasp). next you may backup your current firmware if you so desire, but I just jumped straight to the custom firmware install. plug your header into the port we installed on the radio, then plug into the programmer. make sure the radio power is off and battery pack removed, then plug into USB. in stall drivers if necessary. once plugged in the radio will probably beep continuously, this is alright. click on burn firmware and sit back while the new firmware is written to your radio. If you don't want to use EEPE and are command line savvy, you may use AVR dude directly as well.  unplug the radio once complete, plug in the battery pack and enjoy your new radio! Try out several of the different firmwares available to see which ones you like, and even modify their code yourself if you want a feature that is not available. several of the most popular firmwares include : ER9x, Gruvin 9x, Radioclone, and many others. 


varmon (author)2017-02-21

Hello from FRANCE,

I would upgrade my radio but i would use a USB Fireware Loader USBasp Programmer but I don't know if it could be use to do this ?

Have you please any idea or perhaps somebody already use this kind of USBasp ?

Many thanks, best regards, Michel.

achituv (author)2011-06-09

$53? where?

hivoltage (author)achituv2011-06-09

I got mine here:

astro_wanabe (author)hivoltage2011-06-09

It's only ~$53 if you don't include HK's RIDICULOUS shipping!! The CHEAPEST shipping option is over $20, some options are over $30!! You should clearly state that the cost of this radio is closer to $75+ (depending on where you are, and if you would like to actually receive it sometime soon, it could be closer to $100)!

KenL9 (author)astro_wanabe2016-04-04

Got mine on Amazon with my points card, so got 3% back on card which I use for other amazon purchases. Good card no complicated bs. Free shipping (not prime) from :

New FlySky 2.4G 9CH FS-TH9X-B/TH9B TX Transmitter+R8B RX Receiver Radio Control By Buyincoins
Sold by:RC Mall $88.61Condition:


Ordered on December 31, 2015Order#
112-8855019-5559457 Delivered Jan 19, 2016.

My only complaint is the marginal usage for multi-rotor without er9x. And the no back lite. Bangood states this is an "Upgraded model" but doesn't mention what the upgrade is. Perhaps as a way I believe to deceive you into thinking it has the open firmware, or back lite. Will probably end up springing for er9x if its more quad friendly. Then the backlite too.

I knew loved instructables, but this is great stuff. Thanks!

XTL (author)astro_wanabe2011-06-09

Some of us don't live in the US and so the shipping is much cheaper.
I think its fair to mention its price not including shipping. How urgently you want it is an extra factor.
Try to remember its a small world out there...

hivoltage (author)astro_wanabe2011-06-09

Even including the admittedly expensive shipping its still an amazing deal for what you get.

pietzeekoe (author)achituv2011-06-09


fidibiri (author)pietzeekoe2011-06-09

Actually, he says "Hobby Town"

pietzeekoe (author)fidibiri2011-06-09


fidibiri (author)pietzeekoe2011-06-10

so, we both are right in a certain way: hivltage says $53 @ "Hobby King" and JoeStrout says $54 @ "Hobby Town" so.. I just made a mess of myself.. Thanks

dustinnewton (author)achituv2011-06-09

Like he says, through Hobby King.

Ben The Builder (author)2011-07-01

So I'd really like to know, I looked at getting this remote, and really wasn't sure if it was worth it (maybe it doesn't actually work) and I really couldn't tell from the reviews. I talked to a guy that works for hobbico and he said it's a gamble, does anybody have an advice on whether or not to get the Turnigy 9x?

I have this radio and it works just fine buy the lighted back screen and it works great after dark too. I have used this on rc cars, helicopters, and quad copters I have not needed to change the firmware bit I hear the er9x is very nice I hope this helps I know it's way late after you posted your comment but maybe someone can find it helpful

obviously I got it, and mine works great. Range seems to be very good, it feels pretty well made, and with the addition of custom firmware it has tons of features. Since writing this instructable I finished my RC flying wing and have gone and flown it several times now, and this transmitter has worked admirably. It takes care of the elevon mixing for the wing, as well as adding exponential rates so that I can have both fine control for steady flying and large throws for different maneuvers. Its really an unbelievable deal for what you get: a 9 channel fully computerized 2.4 GHz radio transmitter with customizable firmware.That said, it is definitely a bit of a gamble, since although it has a warranty return shipping to HK costs nearly as much as the radio itself. If you get a good one, this radio is great and a phenomenal deal, but there is a nonzero chance that you could receive a defective radio, although that chance is small.

also, the range can be increased with a better rf module such as one of the ones from FrSky. I use one of their modules in my 9x for fpv flying, and it gets about 3km of range on the stock antenna, or 9-10km with an 11dbi patch antenna.

John_Edward (author)2011-07-17

You can also take the plug gently apart, saving the back pieces, take the cable out, put the plug back together, saw from the end of the plug, and then putting the cable back.
Saves a lot of work as you don't have to solder anything.

That was how I did it :)

As a bonus,the end of the plug has that little notch on the side, and also the extra part for the assembly, making it very simple to remember which side was pin number one.

You just have to check which pin is which cable before soldering them to the microcontroller.

newbeduino (author)John_Edward2015-01-27

I have this radio in its stock configuration and like it just fine it works very well I have used it for rc car, helicopter, quad copter I have heard it's better with er9x or another firm ware but have not needed to change mine. you can but a lit screen to install for under 10 dollars makes it easier to use after dark. hope this helps you.

newbeduino (author)newbeduino2015-01-27

it resounded to the wrong question sorry

The nerdling (author)2013-07-11

what are the pros and cons of this transmitter?
i need one but don't now if i should get this one

SirCheez (author)The nerdling2014-08-05

Pros: Nice look, good features, good firmware, user upgradable, lots of channels, good features for the price, and popular so lots of support available

Cons: No telemetry, annoying beeping noise (user fixable), no backlight, poor documentation, and tricky to modify firmware

radon222 (author)2013-10-01

Why didn't you put a 6 pin or 10 pin male pin header somewhere so you could plug in the USBasp directly? Maybe you make it accessible from inside the battery box so it wouldn't contact anything by mistake.

nerys (author)2011-06-09

Will this radio work with parzone bind and fly models? (are they all compatible with each other in the 2.4g realm?

also how does the turnigy perform compared to the spectrum radio's ?

the 9x is not compatible with any of the parkzone bnfs. however, you can get a module from hobbyking for $30 (the orangerx dsm2 module) that will make it compatible, or they also sell a clone of the dx6i for $65 here:
overall, the 9x a much, much better radio than any of the spektrum models. it has better frequency hopping, more capabilities, has the same range stock or can be cheaply modified to have much more range, and is much more customizeable, not to mention that it is much cheaper as well. also, buying an extra receiver for a spektrum radio costs $50 for a simple 4 channel, whereas receivers for the 9x are $10 for an 8 channel receiver.

hivoltage (author)nerys2011-06-09

pretty sure that this radio is only compatible with its own hobbyking branded 2.4ghz receivers. Theyre cheap though, only 8 or 9 dollars each and available at Theres a couple different ones there that are compatible. If you got a module for this radio you could make it compatible, but for whatever reason they made the stock module connect to the antenna through a hole in the back of the case so while its technically removable you will have to cut the wire and get a module with a port for its own antenna. This is my first and only "real" radio so I don't know how it compares with spectrum branded radios. The only thing about this radio is that you have to realize going in that by ordering it you are taking a bit of a risk because quality control on these is not great and shipping to return it to hobbyking costs more than the radio.

mirakin (author)2011-06-12

I donno i would probably put the USBasp into the controller and change the usb plug to the mini usb so i could just toss a mini usb cord on it... flash my firmware and unplug and go leaving the USBasp in the unit all the time...

the new version (the hobbyking exclusive turnigy 9xr) has something kind of like what you say, in that it has the programming pins already set up, and on the outside of the case, so that you can just hook plug in a usbasp directly to it and reflash it with better firmware. however, the 9xr also comes with a version of er9x already on it, so re-flashing isn't really necessary.

Johnny32 (author)2012-01-29

i would like to install a fw to my 9x tx.
First i need to know what differences are coming between the existing fws to make my choice.
And also i would like to place a knob to use as throttle cut (like the one on the SPECTRUM DX6i). So i have to replace an existing switch or i can add it and add a progam issue and how can i do it (cause i have no knowledge on that).
If u preffer mail me your answer.
Thanks a lot

hivoltage (author)Johnny322012-01-29

There are three major custom firmwares for this radio currently: th9x, er9x and radioclone. they each have a different feature set. I am not sure exactly what features they have that the stock firmware does not because I actually never used the stock firmware, I installed er9x right away. nobody has made a side by side comparison chart or anything like that because the custom firmwares are always updating and adding new features. You will have to go to the project pages for each and decide for yourself which you would like to use. I did not see that the dx6i uses a knob for throttle cut, but I am sure you can use any of the previously mentioned custom firmwares to mix both the throttle stick and a switch or knob to the throttle channel easily.

pastaking (author)2011-06-08

Please don't hotglue the ribbon cable to the chip. Strain could pull the chip off the board!!

hivoltage (author)pastaking2011-06-08

Disregarding the fact that hot glue does not stick strongly and that there's little to no strain on the ribbon cable, if there's something pulling on your radio hard enough to pull off a surface mount chip you have larger problems than a bit of hot glue.

illfixthatone (author)hivoltage2011-12-10

haha my thoughts exactly

pastaking (author)hivoltage2011-08-02

That's a point, but with the hotglue I use it takes a bit of work to pull it of a surface when it is cool. (Sorry for the delay, I lost internet for a while)

Bizwenth (author)hivoltage2011-06-11

I agree with hivoltage on the strain issue, but you be adding heat to the chip by using hot glue, as well if the chip makes any heat at all the glue will help hold it in the chip.

hivoltage (author)Bizwenth2011-06-11

The temperature of hot glue does not even begin to approach the temperatures used to create that board in the first place, they use solder paste applied with a stencil then pick and place machines populate all the parts before the entire board goes into a reflow oven where it heats up to the temperature required to melt the solder and attach all the components. A dab of hot glue on the top is not going to be enough to damage it in the least. as far as the glue impeding the transfer of heat away from the chip, it is just a microcontroller. The datasheet for this device says that even working at its maximum clock speed it will not consume more than 20 mA maximum, about the same current as a single 5mm LED, so heat dissipation is not really an issue.

askjerry (author)pastaking2011-08-06

Not likely going to happen... the chip is soldered to the board by multiple pads... each pad by it's self would likely take 1/2 pound... to yank that chip off the board would take at least 30 pounds... likely closer to 50. As for the glue, it melts at about 180F whereas the solder melts about 600F so that is not going to affect it either.

That chip will likely not even get warm during use... it's not a motor driver or anything of that nature... I have completely encapsulated them in epoxy to make them waterproof... with no issues.


John_Edward (author)2011-07-17

As the firmware is constantly updated, I'd recommend making a connector cable for this.

You can make one from the left-over IDE cable and some two-row pin headers.

Or, if your programmer uses a 6pin ISP cable and you did the internal wiring correct, then you can just stick the pin headers straight between them like I do :P

John_Edward (author)2011-07-17

You can also do the hole for the plug with a soldering iron, an xacto knife and a small square file.

Poke the plastic with your soldering iron, cut the now soft left-over plastic, and finish with a file.
Rinse and repeat, a neat hole in around 20minutes.

Asa J (author)2011-06-14

Love the project. I feel bad for you though, this 'ible seems to have attracted all of the nitpicky grouchy old fogeys from the entire interwebs.
I haven't been keeping up with RC for awhile now so forgive my ignorance, but is it possible to mix for elevons via firmware?

hivoltage (author)Asa J2011-06-14

Thanks! yeah you can create pretty much any kind of mix you want. The stock firmware supported a lot of different mixes but the new firmware supports a ton more. I haven't actually flown anything with this radio yet, but I have parts on the way for a flying wing style plane and will be mixing for elevons with this radio. Don't feel bad, in my experience from a few of my projects being posted on other blogs (lifehacker, gizmodo) the commenters here at instructables almost always have good (or at least constructive) things to say. Whenever my projects have been posted elsewhere commenters have been downright mean.

TampaGeek (author)2011-06-11

The reviews of this radio at the Hobby King site aren't that impressive... have you had any of the problems they've listed? Darn thing seems very unreliable.

mr.incredible (author)TampaGeek2011-06-12

Some of the early reviews are not even for the Turnigy 9x they were people speculating from their experience on the original Flysky version. I've had mine now for about 6 months. I still have the HK v2 firmware on it. It does everything my futaba does and then some. It is a very good radio out of the box, especially for the price. My only issues are with layout of the channel mapping on the receiver. It looks like the firmware upgrade will even fix those problems for me.

hivoltage (author)TampaGeek2011-06-11

That seems to be a classic case of response bias, where only the people who felt very strongly about the product bother to write a review, and since the stock firmware isn't great you don't see to many people who feel strongly about this radio in a positive way. I think that most of the bad reviews were from people who got defective units, and most of those were due to corrupted firmware (HobbyKing flashes the V2 standard firmware on these in house) so following this instructable will fix any of that sort of issue. That said there is a chance that if you order this radio there will be some sort of physical defect since their quality control seems to be a bit lacking, but it doesn't seem to be as common as the reviews at the site suggest. Mine was in perfect condition, no disconnected cables or defective screens/pots/switches or anything. If you get a good one the hardware seems very solid and well built, high quality circuit boards and soldering inside for the most part, especially considering the price.

dialup_prisoner (author)2011-06-09

You don't actually mention where get these updated firmwares. Of course I'm happy to google it myself but are there any sites you recommend for firmware, or RC radio hacking in general? Thanks for the great guide and photos.

This thread at rcgroups is a good place to read about the custom firmwares. each one has its own google code site if you want to download them. rcgroups is a great site for pretty much anything rc related, radios or otherwise.

JoeStrout (author)2011-06-09

Thanks for the very useful instructable, and for the tip about the Turnigy 9X! My son and I are just starting to get into the hobby, and had a bit of sticker shock at HobbyTown last weekend... $54 for a 9-channel transmitter is a no-brainer, especially with your instructions on upgrading the firmware.

pcaffeldt (author)JoeStrout2011-06-09

If you haven't already, you might consider checking out some cheap easy to build great flying planes here.

Especially those planes sporting " KF " wings

66tbird (author)2011-06-09

Great instruct. thx. I've been needing a new tx and didn't want to pay another 9x03. A quick rcg search found a wealth of info.

mr.incredible (author)2011-06-07

Thanks for the great write up. I've seen this several places but yours is the easiest to understand. I too have the Turnigy 9X radio. It is a good radio as it is. The firmware upgrade should make it great.

I think I will go a step farther and make a ribbon cable adapter to go between the USBasp and the new port on the radio. The loose wires is a little messy for my OCD.

hivoltage (author)mr.incredible2011-06-07

yeah it was kind of a quick and dirty connector so I could try out the custom firmwares. If you got a 2x5 shrouded pin header you could install that instead of the ide connector piece and the usbasp would plug straight in. I didn't do that though because the program headers are like a direct line to the MCU and could damage it if any static electricity got in through the pins. for a really clean look you could permanently install the usbasp inside the Tx and just place a mini usb port in the battery compartment. I thought about doing that, but I wanted to be able to use the programmer for other things. Theyre really not very expensive though, cheap enough to permanently install inside if you wanted.

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