Found your exact issue on github. Fix was to do a full chip erase when flashing the lastest firmware.

https://github.com/betaflight/betaflight/issues/4755

Amazing, I didn't find that one myself when searching but that actually checks out!

When I was first running into issues I was trying all sorts of things, and flashed to 3.2.3 - despite not having SBUS working hoping it would resolve the issue. It was only after that that I realised I had swapped the SBUS and S.Port wires. I probably would have had SBUS working fine on 3.2.2 if I had the wires around the right way originally...

I've just upgraded direct from 3.1.7 to 3.2.3 with the Full chip erase option enabled, and immediately SBUS starting working!

Thanks everyone so much for the assistance

That's awesome
Hat's off to Voodoo for finding this page !

Welcome to the forum Maxwell! Likely this would be best started as it's own thread and not linked in to the R-XSR thread. It would appear that you ruled out the hardware on the quad. The only thing left is software related. Can you post a screenshot of your PORTS screen on betaflight? You have to turn SERIAL RX on for the UART that the RX is soldered in to.

Thanks Oscar! Saved me a lot of headaches your post! Just got the pre-build Armattan Rooster and thought I messed something up while flashing EU-LBT compatible firmware to the R-XSR when no input was registered in Betaflight on stick movement. But I just have been holding the button for too long while binding the Taranis. I didn't realise at all that I've switched the modes accidentally!

I just encountered the R-XSR SBUS not working problem.  Infuriating especially since TELEMETRY WAS working.  CAUTION: I put new shrink wrap on the R-XSR and it inadvertently pushed the button for 4 sec and switched modes after setting this up properly.  Rather strange when a quad that was working on the bench all the sudden stops responding to the controller.  Thanks for this post.  It confirmed that I was not crazy!

I just want to say thanks to Oscar who mentioned that holding the BIND button down causes the RXSR to switch to CPPM mode. I have been struggling for 2 weeks trying to get my Matek 405 board to talk to the Taranis receiver. One 4 second press and everybody is talking to everybody else!

OMG .. i was banging my head on this rxsr fport thing forever. This was a revelation. Thanks Oscar!

Thanks Oscar!

Hurray!!!!


I'm (near) totally new to the hobby ... things like that are real killers 

so glad I found this thread! I just set up my first full DIY quad, and right off the bat updated my jbardwell f4 to the newest Betaflight (4.2.6). After screwing around for ages unable to get my RXSR to bind, I found your post Shambl3r. Unfortunately I still dont know what firmware the receiver is running, but reverting to Betaflight 4.0.2 solved my issue. Thanks so much guys!

Non of you guys are crazy. I got rxsr as well no blue led telemetry not working I thought the receiver was broken so I ordered a new one and as soon as I put the updated firmware on it the blue light never came back on now this all happened on a xlite pro radio, again you guys are not losing your minds it’s the firmware now I’m trying to figure out how to get back to the factory firmware

I have quite a few small quads with d-8 spi RXs, and with 2 fairly new RXSRs failsafeing in front of me... Helped me make a simple decision to finally pull the trigger on Crossfire

Thanks !!!! I thought I go crazy.... didnt know I could switch this thing