Ok I ran that several times and the UART 3 stays on but the serial rx stays as is (off)

I wonder if your FC is defective.

The reason I specified the CLI command to switch off the Serial Receiver Protocol is because that is what it was set as in your original Butterflight "diff all" (see post #18 in this thread), so I assume your quad has a PPM or PWM receiver installed which is quite possible for a 5 year old quad.

I think we need to see some photos of your quad so we can try and see what hardware it has in it. FC, Receiver, VTX, ESCs etc. and in particular the wiring that connects the receiver to the FC.

It's always a gamble buying a used quad. It's quite possible that you bought a lemon and the seller knew it had a problem which is why they were trying to offload it to someone who didn't know any better.

OP mentioned he wired up a Crossfire module in the first post.

Good point. I totally forgot about that with all the FC flashing issues taking things off on a tangent.

I've never seen the issue that the OP is having before, so I think this FC is unfortunately a lemon. The eBay seller probably knew it was fubarred.

@OP - I would contact the seller and ask for a refund. If that doesn't succeed then raise an eBay / PayPal dispute.

Well the seller sent me videos of it flying so i assume its only a matter of incorrect configuration, but who knows. Also i bought it over half a year ago, so I doubt I could even get a refund.

It looks like you might have the wiring backwards. Crossfire Nano RX needs to be wired to TX on FC. And Nano TX to RX on FC.

Well I haven't changed the wiring since i got it. And the previous owner apparently had it flying. I might try to hit him up again and see what he says

(19-Oct-2023, 03:38 AM)hobbyczar Wrote: Well I haven't changed the wiring since i got it. And the previous owner apparently had it flying. I might try to hit him up again and see what he says

Can you show a clearer photos of the wiring from Nano to FC? A lot of wires are overlapping and difficult to see.

I am pretty sure that the wiring is incorrect.

The wiring from the Crossfire Nano RX to the FC is definitely wrong. It has white wire Channel 1 (TX) going to TX3 on the FC and yellow wire Channel 2 (RX) going to RX3 on the FC. That is incorrect and won't work.

Regardless of that, even if the wiring is corrected that's not going to fix the issue where you seemingly can't switch on Serial RX for whatever reason, so you will still have that problem.

I think the seller has probably duped you by just showing you a video of a different quad flying, or of that one flying before it was subsequently fubarred. It was definitely never flying with the receiver wired up like that and with Serial RX switched off.

I messaged the seller to ask for more details. Please note I did reset the settings for the drone at one point so the first dump files i sent were not the orignal. I dont remember if i mentioned that. Below are some pictures of the wiring. Hopefully this helps. Also looking at the sellers about page (this was not here when i bought it) it says "I'm just trying to survive $  please forgive me" . Lol i thought that was kinda suspicious but it is unrelated.

The wiring is wrong. You need to switch the yellow and white wire. Either in the FC or on the receiver.

Your incorrect Crossfire Nano RX wiring issue is already in hand, so I'll turn to the issue where you aren't able to switch on the Serial RX setting.

Have you tried a different computer? If not then try that.

Do you have an Android device? If so then install the SpeedyBee app (click HERE) and try that with an OTG cable connected between the Android device and the FC. The SpeedyBee app has the Betaflight Configurator, EmuFlight configurator, and INAV Configurator built into it. You can also use the SPeedyBee app if you have an iPhone, but only via Bluetooth and not a cable which means with an iPhone you would also need a SpeedyBee Adapter (click HERE) which works over Bluetooth.

The seller assures me he didn't rip me off. whatever. on another note, I'm going to get a soldering iron and change the wires. Do I change it on the fc or the receiver? Also, I have an android phone I just don't have the right cable to connect my drone, so I can order that and try that next. Thanks a lot for your help guys i want to get this drone in the air