[DIY 3DR radios] how to flash the HM-TRP

Hello everyone and merry christmas hope everyone is doing fanstastic.

i have done some reshearch on the topic , but still i dont 100% feel comfortable proceeding with it .

All my arial platforms (multirattors and fixed wings) are using the original , 3DR telemetry radios on 915mhz.
But due to 3dr going out of business all these years ago , im still not able to find a good replacemt .
Mro’s option cannot sync up with my exiting radion on the GS and thus , i cannot add any new UAVs on my fleet .I had the idea , since i have the schematics and the HM-trp mondules are readily available on ebay and other sites what if i make one my self ?


while shearching on the web about this , i found that

  1. i whould have to flash the bootLoader hex on it using a C2 programer
  2. Then , using mission planner perform the usual setup for mondule .

To address the first i ll need a C2 programer ,uppon googling i found that C2 programers arent cheap , but someone made a emulator using a arduino .
Then i found .hex files from a thead over at DIYdrones

has anyone tried doing this , is it worth the hastle ? (i have considered herelink but my setup and workflow cannot be altered to account different GCS and the diferant on board radios)

Thanks in advance i wish everyone a happy new year .

They should if they are on the same firmware version.

In any case go here:
SiK radio

Long time ago I used this cheap “C8051F MCU Emulator U-EC6 USB Debug Adapter” to flash the bootloader. You can find the adapter on ebay.

im updating everything via Mission planer , they report to be on the same f/w version and i manualy set them on the same Net ID . no dice… I cannot get them to communicate with my existing fleet

What hexfile did you use ? the ones from the DIY drones thread?

Do the pair of Mro radios work together, they just don’t work with your other radios?

They paired togeter but not with my 3dr radios . Yes they were on the same frequency

The only SiK radios that don’t communicate with other SiK radios are the RFD900X series.

I have an mRo that syncs perfectly with other brands…which I discovered entirely by accident when I had two of the three brands I own powered simultaneously.

The SiK radios must have the same “Format” Parameter to sync.

Older modules often have version “1.9” installed which have Format parameter “25”. They do not sync with newer modules running version 2.0 with Format parameter 26.

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Right. This thread has some addittional info tools and firmware attached.
3DR radio firmware

From aliexpress, you can buy HM-TRP modules with preloaded 3Dr bootloader :slight_smile: HM TRP 100mW wireless data transceiver module 433/868/915Mhz TTL transparent transmission 3DR model aircraft APM flight control|Replacement Parts & Accessories| - AliExpress

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I dont have any MRO in hand atm , but i have some generic ones (still with HM-TRP) that they would too not sync . ill try a reflash and see .

Hello everyone again .
i got my hands on a 915 mro set that i borrowed to test what @RainFly sugested .

on the one side i have one of the Mro modems : image

and on the other side the original 3DR radio modem : image

As you can see they are not syncing up . even with the same Format parameter and f/w

Try to get some distance between the modems.

Tried this . from having the antenas touching up to the other side of the bulding … the green light stays flashing