Hi. New to the forum but been flying FPV since forever. Built possibly 10+ quads and numerous wings and planes. 
Always been using Frsky for my quads, but wanted to go back to Spektrum a while ago as I have been using it for LOS planes and helicopters.
When Spektrum released their SPM4650 I wanted to give it a go and succeed to get it working with Betaflight firmware 4.1.0 on an Omnibus F4 SD AIO OSD board. Being happy with the setup I built a second quad with the exact same setup and got it working too. 
I have been flying with these two for a couple of years, and decided to upgrade to BF FW 4.4.2 on one of the quads. But now I cannot for my life get Betaflight Configurator to identify the receiver. 

setup that has been working since initial setup:
Omnibus F4 AIO OSD
Spektrum SPM4650 soldered to TX1 and activated Serial RX in BF
Receiver mode set to Serial
Protokol set to SPEKTRUM SRLX2

When I first set it up, i think it was in 2019, you had to do a couple of additional CLI commands, but as I understand that would be obsolete in the newer versions of BF. 

Since you normally use RX, I moved the signal cable from TX1 (for some reason, Spektrum instructed to have it on TX) to RX1(D) instead, but still no luck. 
Anyone here having an idea what to try next? Or is it something obvious that I have missed?

Sounds like you are having the same issue I was having that I posted about here: https://intofpv.com/t-spektrum-betafligh...betaflight

You should have your RX signal wire connected to a UART TX pad on your FC, so you had that correct to start. But I am guessing you updated the FC firmware before trying your link in the Receivers tab. What you need to do is go back and update the firmware again, but before you download and update it, on the firmware page in BF there is a drop down menu for "Radio Protocol". You have to select SRXL2 and then update the firmware. Assuming you have "Serial (via UART)" and "Spektrum SRLX2" selected on the Receivers tab and the correct UART selected on the Ports Tab, all should work fine with your link after that.

Best of luck!

(06-Jun-2023, 05:09 PM)Skavage Wrote: Sounds like you are having the same issue I was having that I posted about here:  https://intofpv.com/t-spektrum-betafligh...betaflight

You should have your RX signal wire connected to a UART TX pad on your FC, so you had that correct to start.  But I am guessing you updated the FC firmware before trying your link in the Receivers tab.  What you need to do is go back and update the firmware again, but before you download and update it, on the firmware page in BF there is a drop down menu for "Radio Protocol".  You have to select SRXL2 and then update the firmware.  Assuming you have "Serial (via UART)" and "Spektrum SRLX2" selected on the Receivers tab and the correct UART selected on the Ports Tab, all should work fine with your link after that.

Best of luck!

Jeeez! Thank you! You saved me from a complete meltdown. I thought I had lost it completely. 
One thing that I noticed though, having the signal soldered to the wrong pin and it refused to open the serial port. After some more hair pulling, I soldered the signal wire to the correct pin as it was before and - Voilà!

Glad to hear it worked out for you. I was scratching my head and getting pretty frustrated also. I got lucky when I was reading this thread: https://intofpv.com/t-speedybee-not-talk...betaflight At the end it mentions something about "segments" when flashing the firmware. I had no idea what that meant but checked out the firmware page and discovered the "Radio Protocol" dropdown and re-flashed after choosing SRXL2 and it worked. So I can't take credit, just got lucky finding someone else with a similar issue.