Jeti firmware 4.20 – What to expect?

In my opinion one of the best updates for long time, that’s for sure. Let’s do a quick run-down on what to expect.

New functions

Ability to smooth curves. This is something that I find very valuable, making better functioning curves is so much easier now, surely adds to even more precise control of channels:

Even more precise functions for dual rate and exponential functions. Also possibility to use them as proportional:

This is something I have waited and wanted for a long time, now it’s possible. A possibility to use trim-buttons as switches. There’s two possible ways:

  • Momentary 3-position switch
  • Rotary function

The momentary 3-position is clever. up- and down-positions (or left/right) are active only as long as you press the button. As a heli-guy the rotary-function is where it get’s interesting. In the middle the switch value is 0%, after that every press up changes the switch proportional value with %-amount of defined trim-step. This means we can easily build a function for example for gyro’s bank-switching, flight-mode-switching or basically anything. In essence, it’s now possible to use trim-buttons as sequenced switch with up to 200 positions, how’s that for versatility?


Update also includes up-to-date bin-files for SBEC30D, MFlow2, Brain FBL, 3Digi, Vortex and Spirit. I have to say I really like the trend where more and more FLB-units are getting integrated. I just love the way I can adjust my Spirit straight from transmitter.

Usability add-on’s

As usual, some added “small” functions too:

  • A warning is displayed if you want to turn off radio with model turned on
  • After creating a model there’s now possibility to do binding right away, very convenient
  • Additional system sound, “Receiver reboot”


Corrections includes for example:

  • Preflight positions check dialog is fixed
  • All channels transmitted immediately in 24-channel mode
  • Spanish voice-files added
  • Telemetry-page automatically jumps to page one if model is loaded
  • Audio-folder now supports 500 files compared to old max 200.
  • The “Sym.” button in the items of Fine Tuning menu now remembers its state even if you exit the menu

Anything else?

Oh yes. I saved this to last. DC/DS-16 will get LUA! In the beta-version I’m testing LUA-functionality there is two update versions, one “16-standard” and one “16-lua”. I do not know if this will be the case when update is released or what the differences between versions are but I know the LUA-version works fine for me in DS-16. The release of “LUA 16” does not have any mentioning of -14 and documentation only mentions 16 so it’s safe to say that -14 will not get LUA.

There are some obvious and some less-obvious limitations. The main difference between -24 and -16 is hardware as discussed many times. This is also the base for the limitations in 16 when compared to 24-series:

  • 24 can play Mp3, 16 plays only wav
  • 16 has no vibration support (Unless you use RC-Thoughts Jeti Vibrator…)
  • 16 does not benefit of colors

LUA in DC/DS-16

So, what’s new in 4.20 LUA and what can be done in 16? There are some very useful new command available, for example:

  • getProperty, ability to read several system properties, like the long-wanted model-name. There’s also brightness, backlight, wireless mode etc etc
  • setProperty, ability to set some values like different volumes, backlight brightness etc. How about automatically use higher volume on warnings when model is in the air? This is a valuable add-on for the total user-experience. Also it’s now possible to control wireless mode from LUA, for example teacher-student etc.
  • More graphics functions like draw circle, ellipse
  • Possibility to use clipping rectangle, meaning a possibility to define a are where drawing is not allowed on outside of
  • Possibility to add icons, in 24 you can use jpg/png too, in 16 only icons.
  • Possibility to set form title. This is something I have wanted from day one. Currently the title for the application is fixed (ie. the app name) but now it can be set straight from the LUA-app. Great for those multi-form (multi-screen) apps
  • Possibility to ask a full-screen question with definable text. There are times when one would like to ask the user of confirmation, this is a great add on.

LUA-coding limitations in DC/DS-16 are dependent of a few things:

  • Runtime memory allowed for LUA-apps is 30kB (Basically unlimited in -24)
  • 2 applications allowed at same time (10 in -24)
  • 4 LUA-controls allowed (10 in -24)

How does for example RC-Thoughts Jeti Tools apps work in 16?

Well…. Does and does not. Since I heard about the limitations I have tested the apps. For example the Momentary to Latching works fine with a very minor adjustment, had to remove the fifth control since four is max. Also the Snapper works just fine apart from a very small display difference that is easy to fix.


Others did not do so well, they failed to memory errors since they simply take too much memory. I did some research for some of the apps like RFID. As stated we have 30kB to use for LUA in -16, the RFID-application takes 89kB in runtime. I made some cuts like lowered battery amount from 15 to 5 and so on but only got down to something like 60kB which still is double of allowed. I do have some ideas how to make it work with enough functions to be useful but that will be a true uphill-battle where I just cannot make any promises. We shall see on that one. The 30kB is very little, but one thing is for sure, it’s better than nothing!

So? And when?

In my opinion, one of the best updates to 16-series in a long time. Very nice features we now can enjoy. I know there’s been discussions like “will 16 be forgotten by Jeti now that 24 is out?” but I think those talks can now be forgotten.

What comes to when Jetimodel is releasing 4.20 to 16 and to 24 with added LUA-possibilities, I don’t know. Jetimodel is as of today off for holidays until 30th this month so I think it might be safe to say that the update will be available “next year”. I kinda like that, give’s me some time to work on the LUA-apps for -16.

Stay tuned :)

8 thoughts on “Jeti firmware 4.20 – What to expect?

  1. Astonishing how already perfect can still improve :) Have to study LUA, maybe it is not too difficult… Thank you again for the information.

  2. What's LUA?
    Also, I know Jeti seems to only cater to power users these days but don't you think that a radio as sophisticated as a Jeti could manage to do better than label multiple servos on the same control surface better than Aileron1, Aileron, and Aileron1?

    1. About naming the servos, I have to say yes, I agree to 100%, that is for some unexplained reason apparently not important to them even when this issues have been up numerous times.

      What comes to "Jeti seems to only cater to power users these days" on the other hand I have to disagree with you. It is true that Jeti's transmitters are very power-user oriented. I's like to think that it's purely due the great amount of possibilities these transmitters offer. Having a vast amount of option is not in my mind the same as being for "power user's only", I'd like to think it as versatility, possibilities, more suitable to anything.

      All the "basic stuff" in Jeti's transmitter work as they should, it's only natural that most of the updates and add-on's are to extend the capabilities. With possibilities and variations comes also the imagination of "difficult, pro's only" etc. The fact still remains, one does need to use all the features, they are there if one sometime in future will use them :)

      Before my first Jeti transmitter I could not care less about the transmitter, it was limited by default. I'm not hindered by that anymore and I simply love it. I can do almost anything I want, even the most complicated tasks can be automated and that is what I'm after, do more with less input and action while flying.

  3. So, with this update giving LUA to the DS/DC-16, does that mean Jeti Studio is applicable to us as well?

    1. I don't see why Jeti Studio would not bee applicable right now? Only 24 reference in Jeti Studio (that I can see) is the emulator which is a 24-emulator. All functions in the emulator does work in 16 too if they exist in 16. Have I missed something?

  4. Ok, I am still new to Jeti, had the 6 for several months but haven,t been home to really get into. I was under the impression that LUA was only applicable to the 24 series.

    1. LUA have been only for -24 so far, that is correct. But Jeti Studio is so much more and it's for 14/16/24 :)

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