Engel Modellbau + Technik

What is behind the UNIVERSAL ACCST FIRMWARE?

The Universal ACCST is firmware that can be installed on many FrSky ACCST (D16) receivers. Currently these are the X4R, X4R SB, X6R, X8R and the RX8R and RX8R Pro. We are working on making the firmware available for other ACCST receivers. Please check our forum frsky-forum or our website www.engelmt.de for more information.

The target was quite simple in the beginning. We wanted to develop a more user-friendly ACCST firmware that fixes existing bugs in the FrSky firmware and allows us to continue to distribute the ACCST receivers in the long term even if FrSky should stop distribution. Corresponding agreements with FrSky exist. The hardware production will continue to be done by FrSky. We do not work against FrSky but in agreement!

This new firmware has the advantage that it is much more comprehensive than the FrSky firmware. So it recognizes itself whether from the transmitter with the V1 or V2 firmware or with LBT or FCC is sent. This means that the Universal ACCST combines four firmwares in one. Your transmitter can be FCC or EU LBT and V1 or V2 and still the Universal ACCST firmware will just work.

Is that all?

No, we have dealt with every problem known to us at ACCST. And we did so regardless of how infrequently it occurred. The result is a firmware that simply works, and works VERY well.

A few highlights:

The "Tuning" function was added to optimally tune the receiver to the transmitter. The result is a much more stable transmission system.
To better monitor transmission quality, the VFR (Valid Frame Rate) value is transmitted to the transmitter via telemetry and can be displayed on the normal telemetry display.
The so-called close-range problem, i.e. the problem of "overdriving" the receiver has been solved. So no more error message in the close range "Telemetry lost, telemetry restored".
Eliminate the risk of a failsafe at close range when transmitter and receiver are very close to each other.
Rare telemetry data errors (unrealistic values) with weak RF quality have been eliminated.
A new function for double binding (two transmitters) has been added.
Protection against flashing an incorrect firmware version to the receiver.
Switching from SBUS to PWM via script. The SBUS output of a receiver can be set to PWM in a setting script. Thus, for example, a 6-channel receiver can be extended to 7 PWM channels.
Extended telemetry. You can read out further telemetry values via a telemetry script. For example, the firmware version of the receiver or CRC errors, etc.

How can I flash the firmware to my receiver?

The Universal ACCST firmware has a special protection procedure to prevent clone manufacturers from using the firmware. The firmware is freely available for download. So is the activation lua script. To use the receiver it must be unlocked by an unlock code. This activation code is available under the order no. ABLFreischaltCode for a nominal fee of 3 Euro. Any subsequent updates can then be downloaded from the network and installed by the user.

New receivers that are explicitly advertised with the "UNIVERSAL ACCST firmware" already have the "firmware" installed. If, contrary to expectations, you want to flash back to the FrSky firmware, this is possible at any time. The firmware, updates, manuals and Lua scripts are available at FrSky-Forum/ or in our store Download ACCST-UNI-Firmware.

Flash and unlock the firmware
Download the appropriate firmware, unzip it and flash the receiver as you know it from a FrSky receiver update.
Download the Activate.Lua and copy it under Scripts to your transmitter.
Now bind the receiver with your transmitter.
Now open the Lua script and read out the code which will look like "5548 6789 2014" Enter this code under remarks in the order of the activation code (Order No. ABLFreischaltCode). If you order the item more than once, then enter the code from all recipients under remarks. As soon as we have received the invoice amount, we will send you the activation code.
Switch on the receiver again and open the Lua Script. Enter the code we sent you at the place "Code: 888888" and confirm the last number/letter with "ENTER".
Now scroll to "end". "end" changes to "Send". Click on "Send" to start the transmission of the code to the receiver. As soon as "Activated" is displayed the receiver is unlocked and fully functional. Later updates are possible without further activation codes.
If necessary, bind the receiver again as described below.