Receiver (P1RC) Not Passing Stick Data After BF Update – Need Help with UART/Serial Settings

[smoky kettle]

Hi everyone,

I’m having trouble with my DJI P1RC receiver after updating my Betaflight firmware. Here’s my situation:

Setup:
• Flight Controller: Matek F722SE
• Firmware: Betaflight 4.5.1 (previously I was on 4.2.1, and the receiver worked fine with the old configuration)
• Video System: DJI Air Unit (OSD is working correctly)
• Receiver: DJI P1RC (digital receiver)
• Goggles: I rooted my goggles using FPV.wtf and installed the custom OS.

Wiring:

For the OSD, I’m using UART3 (which has the white wire on TX3 and gray on RX3 – this wiring produced the default DJI OSD correctly).
The receiver was originally wired on UART4 with a yellow signal cable.
After the update, the OSD displays properly, but the stick inputs from the P1RC remain static at defaults (all channels at 1500 except throttle at 885), meaning I can’t arm or change flight modes.

Troubleshooting Steps I’ve Taken:

Receiver Port Configuration:
 - I’ve tried connecting the receiver to UART4 (yellow cable) and also rewired it to UART6.
 - I attempted to configure the serial port via CLI (e.g., serial 4 64 115200 57600 0 115200 and similar for UART6) but received errors.
Receiver Tab Settings:
 - In Betaflight, I set the “Serial Receiver Provider” to CRSF and experimented with both AETR1234 and TAER1234 channel maps, but the channels remain static.
Inversion Settings:
 - I toggled the inversion (serialrx_inverted = ON/OFF) with no change.
Firmware and Binding:
 - The receiver was working before updating to 4.5.1, so the wiring hasn’t changed. I’ve also verified that all firmware is up-to-date.
Goggles:
 - I’ve rooted my goggles using FPV.wtf and installed the custom OS, and the OSD is now working fine.

Before the firmware update (when I was on BF 4.2.1), my receiver worked perfectly with the same wiring. Since updating to 4.5.1, I’m not getting dynamic stick data, which prevents arming or switching flight modes.

[plush cargo]

✨AI-Generated response✨

Please ensure that the UART you are using for your receiver is correctly configured for "Serial RX" in the Betaflight Configurator "Ports" tab, and that the "Peripherals" dropdown is set to "CRSF". Double-check these settings as they may have been reset during the firmware update. Refer to the documentation on Serial Port Configuration for more details.

Also, in the "Configuration" tab, verify that the "Receiver Mode" is set to "Serial-based receiver" and the "Serial Receiver Provider" is "CRSF" under the "Receiver" section. The Receiver documentation may provide additional guidance.

[quick merlin]

Please generate a support ID and send it here

!supportid

[snow abyss]

Betaflight Support

Submit Support Data

1. Open the CLI tab
2. Click the "Submit Support Data" button

• Optionally enter a brief description of the problem
• Wait for it to finish

3. Copy the resulting support ID

Check the image below for visual steps:

[smoky kettle]

unable to connect to server error HTTP 400 with the online betaflight app and locally but here is the document with the requested file

[smoky kettle]

!supportid 9d43c822-38e5-4ade-9fbc-415746b46a87

[snow abyss]

Betaflight Support

Submit Support Data

1. Open the CLI tab
2. Click the "Submit Support Data" button

• Optionally enter a brief description of the problem
• Wait for it to finish

3. Copy the resulting support ID

Check the image below for visual steps:

[vital jacinth]

Do you have a diff saved from before you updated?

The receiver built into the air unit uses SBUS, not CRSF

Reflash Betaflight with SBUS support by selecting SBUS under receiver protocol when flashing

[smoky kettle]

Thank you so much for the suggestion—I really appreciate your help! Yes, I do have a diff saved from before the update, so if all I need to do is re-flash with SBUS support selected, that would be fantastic. I’ll give it a try and let you know how it goes. Thank you again!