# FAQ / ELRS bound but no inputs in firmware

### Possible causes:
* ports-tab: pertinent UART's `Serial RX` toggle must be enabled.
* RX/TX is mistakenly soldered in reverse.
* some FC's dont like it on UART1, try another UART.
* protocol is mistakenly not setup in receiver tab. rectify with:

feature RX_SERIAL
set serialrx_provider = CRSF
set serialrx_inverted = OFF
set serialrx_halfduplex = OFF
save

* RX/TX should both have same **model-match** setup. Use the ExpressLRS Lua to set **`Off`**(preferred) or **`On`**(with ID's that match the RX ID's).
* cloud-built HEX did not include CRSF protocol. (Betaflight 4.4 and later)
* TX must be powered on before RX.
* TX and Betaflight should both be same channel order. e.g. `AETR` or `TAER`, etc.
* Prefer to use full UART, not SBUS. SBUS may or may not require inversion (`RCVR_INVERT_TX`). see ELRS documentation. Inversion can be done in Betaflight and/or ELRS firmware (Prefer ELRS). Only one combination will work proper.

### Rare causes:
* in ELRS LUA script, set Model Match to `On`, then set it back to `Off`.
* for Betaflight 4.4 and later, Configurator 10.9 will force "`CRSF/GHOST/SBUS`" as the default protocol. If you use [Configurator 10.10](https://github.com/betaflight/betaflight-configurator-nightlies/releases), you can choose **`CRSF`** *only*, which is preferred.
* sometimes receiver tab needs to be manually set when coming from older firmware. CLI paste may not work.
* i saw an issue-tracker with some `3.2.1` issue on some RX with Windows ELRS-Configurator. Try to upgrade or downgrade to another version. Also try cloud-built ELRS via https://expresslrs.github.io/web-flasher/ (use Chrome, not Firefox) in case local-building is the problem.

### ELRS documentation on the subject:
* Useful! https://www.expresslrs.org/quick-start/troubleshooting/

#### off-subject:
* binding-phrase issue https://youtu.be/cOp5Jdms7xQ?t=152
* ELRS troubleshooting https://youtu.be/ho4vLbu3H8U

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