Firmware Files

A number of firmware image files are compiled for every new MULTI-Module firmware release. Use the MULTI-Module Firmware Download site to download the correct file for your module:

Standard File Naming

The standard firmware file names follow this pattern:

multi-[module type]-[radio type]-[channel order]-[telemetry inversion]-[firmware version].bin

The parts of the file name are explained below.

Module Type

Determines the type of MCU the firmware was built for:

  • avr - for older MULTI-Modules with an ATmega328p MCU

  • stm - for MULTI-Modules with an STM32 MCU

  • orangerx - for OrangeRX modules running MULTI-Module firmware

If you don't know what module type you have, it is probably stm.

Radio Type

The firmware of the radio the module is (or will be) installed in.

  • erskytx - for radios running the erSky firmware

  • opentx - for radios running OpenTX firmware

  • ppm - for any radio which uses PPM Mode

Channel Order

The Expected Channel Order for the firmware image.

  • aetr - expects to receive channel data in AETR order

  • reta - expects to receive channel data in RETA order

  • taer - expects to receive channel data in TAER order

The default Expected Channel Order is AETR.

Telemetry Inversion

Specifies whether or not the telemetry signal from the MULTI-Module is inverted.

  • inv - telemetry signal is inverted

  • noinv - telemetry signal is not inverted

Use noinv firmware for internal MULTI-Modules, inv firmware for external MULTI-Modules

Firmware Version

The version number of the firmware.

Firmware File Examples

Some examples to help select the correct firmware file:

Module Type

Radio Type

Channel Order

Firmware File

Jumper JP4IN1-SE




Jumper T16 Internal




iRangeX IRX4




Other Firmware Files

A small number of files are compiled for debugging or development purposes. These files are only produced with AETR channel order and with telemetry inversion enabled.

These firmware files are not for general use and should only be used when testing.

Serial Debugging

Firmware is produced for serial debugging using either an internal or external USB-to-serial adapter, or the MULTI-Module's native USB port.

Serial Debugging firmware outputs diagnostic information to the module's serial port during operation.

Serial debugging firmware is named in this pattern:

multi-stm-[radio type]-aetr-inv-[debugging type]-[firmware version].bin

Debugging Type is either:

  • ftdidebug - debugging using a USB-to-serial adapter

  • usbdebug - debugging using the native USB port

The usbdebug builds do not contain all the available protocols because doing so would exceed the flash memory of the module.

See the Serial Debugging page for more information:

Protocol Dumping

Protocol Dumping firmware enables the radio to capture and decoding RF transmissions from other RC transmitters which use the common XN297 RF module. This can be used to reverse-engineer unknown protocols so that they can be added to the MULTI-Module.

Captured data is displayed via serial output.

Protocol Dumping firmware is named in this pattern:

multi-stm-[radio type]-xn297dump-inv-[debugging type]-[firmware version].bin

Protocol Dumping firmware only includes the XN297L dumping protocol and cannot be used with any models or receivers.

See the Protocol Dumping page for more information: