Hi everyone!
I have lost almost all my hope on resolving this one.
The short story is: inspired by my friend I have decided to resurrect my quad which I have started to build years ago. I have a frame, MATEK F411 ONE FC, ESC's and motors.
So I bought a radio X9D SE 2019. Updated betaflight and esc's software but here started problems. I couldn't bind onboard SPI with my taranis and turns out Frsky removed D8 so that wasn't possible anymore. So I bought archer RS with Access. That binded without problems but there is no communication between FC and receiver.
I have searched all internet tutorials on this including Oscar's guide for FPort configuration but nothing is working. I have constant RX Failsave in betaflight. Is that F411 ONE too old for this receiver or am I missing something? Matek tells that there is support for FPort and gives also instructions. I have tried every combinations TX1, TX2, SPort, SPort Inverted, also every combinations of betaflight settings - serialrx_inverted, serialrx_fullduplex. No luck. I have ordered F7 because I have planned upgrading but I don't want to throw 411 into bin. Every help much appreciated. Thanks.

To use FPORT on an FrSky ACCESS transmitter / receiver you need to switch on (tick) the "F.Port" option for the receiver under the "Internal RF" section on the SETUP page for the model. Did you do that?

If you didn't then then take a look at the following post which shows you how. That's on an FrSky X9 Lite transmitter but the procedure is the same on an X9D 2019...

https://intofpv.com/t-r-xsr-fport-connec...#pid106590

Thanks for the tip. Unfortunately I did that.

I have updated Internal RF and Receiver software. I assume that if I have success register and binding with receiver then this link is working good right?