I have the set of 3DR telemetry radios. One of them connects just fine (blinking green), but the other is just solid red. It’s not accessible by the computer or APM. I swapped the radios between the computer and APM and the one that flashes green does that on both and the one that is solid red is also red on both. Could it be a bad radio? Any ideas? Thanks.
-dave
Hi Dave,
It seems to be a defective module, a solid red led indicates the module is in firmware update mode.
copter.ardupilot.com/wiki/common … tatus_LEDs
If you bought your radios from 3DR, you can ask for assistance sending an email to help@3drobotics.com providing your order number.
Thanks RogelioN,
I did buy it from 3DR and I just emailed them with the info. Thanks for the quick help Hopefully 3DR can sort it out.
-dave
Maybe this module has uploaded bootloader only, without firmware?
You can try to connect it to PC, start 3DR Radio Config tool (vps.oborne.me/3drradioconfig.zip) and perform firmware upgrade - this may save some time 
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If you want to try you, I think you can achieve the same using mission planner, initial setup, 3DR radio, upload firmware
Hi,
I have the same problem and connecting to the PC via FTDi doesn’t work… Did you find a solution?
Thanks for your help
Try “Firmware update” button.
If it fails - check, if maybe it’s in “force bootloader mode” due to shorting the CTS and GROUND pins on the radio while powering on: