Could not put in to bootloader mode radio telemetry

Hi all!
Help is needed!
I had a problem connecting radio telemetry modules.
When I try to update the firmware of the air unit it gives an error: “could not put in to bootloader mode”
SiK 2.2 on HM-TRP - ground init Format - 26
SiK 1.9 on HM-TRP - air unit Format - 25

How are you connected the the air unit? You’ll need to connected by USB to update it.

The air unit does not have a USB input. I connected it to my Pixhawk and tried to do it through it. When connected to it, it is visible in the mission planer. Was I doing something wrong? If it’s not correct. tell me how to do it correctly.

What make/model of radio is it? If it doesn’t have a USB input you might need an FTDI cable.

3DR 433Mhz 100mW / 915Mhz 500MW Radio Telemetry Air Ground Data Transmit Module for APM2.6 APM2.8 Pixhawk 2.4.8 Flight Control bought on aliexpress


What specific FTDI cable is needed? There are a lot of them on the Internet, you don’t want to make a mistake.

One like this. Jumpers for 3.3 or 5V is handy. It’s hard to know if you are getting a real FT232RL Chip so don’t buy that is $5…

what voltage should I apply? 5v or 3.3v?

5V is good. For some other boards, like an ESP8266, it’s 3.3V.

Thank you! I’ll try.

Alternatively you can use serial passthrough to connect to the air side radio.

Thank you. How can I do that?

MavLink logging backend and appropriate software on the RPi I don’t remember the name.

If you have a laptop you can try using WFB-ng. Digital video is better quality than analog.

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Thanks! I will check it.

No! I am asking for the onboard drone camera. I have a USB camera onboard in the drone which outputs the UVC video, is there any video transmitter which can transmit that video to ground or any converter which I can use onboard and convert the UVC video to analog and use any VTX for transmitting it to ground.

Thanks. Hoping someone can help me in that.