You've either just built or received a fresh iFlight Quad (BNF) but you won't get it to arm?
Well, that might have different reasons...
In the below picture, you can see the default screen of your Betaflight Configurator. If you don't know how to get there, please check out the following article first:
https://iflightrc.freshdesk.com/support/solutions/articles/48001149209-general-guide-iflight-bnf
If everything below can't help, please check out some resources on YouTube in further detail:
https://www.youtube.com/watch?v=N8oMMG2kmns
And just to mention it, even if most people already know...
ARMING can only be done when the throttle is at ZERO position and USB is not connected! Then flick the AUX1 switch which is usually configured at the far left of your Radio Control and gently lift off.
The picture shows a box called "Info" on the right side. In this example, we can see the error message "RX_FAILSAFE" which shows up when the RX (Receiver) is not connected, not properly connected, not set up in Betaflight or not powered up (make sure you plug in your battery to power up the 5V BEC on your Flight Control )
The second error message is MSP which just disarms the Quad while you are connected to USB (safety mechanism).
The second picture below shows the Ports tab in the Betaflight Configurator. Please make sure all the ports are properly set up and the Serial Rx is set up at the correct UART.
To confirm this, please check out our Google Database for all the Wiring Diagrams and more:
https://drive.google.com/drive/folders/1r3MNTBNYSzGeRXQg45j4IJVoW1Xjk7Y0
The third picture shows the Configuration tab, where you can verify the correct protocol for your Receiver. Frsky receivers usually use SBUS or F.Port depending on your setup, TBS/ELRS uses CRSF, and DJI components use SBUS as well and even offer an option for a faster protocol that has to be manually set in the CLI (check out this article）
The fourth picture below shows the receiver tab in the Betaflight Configurator. Is the signal valid, the RX properly configured and powered up？ You'll see the sliders moving when you move the sticks or aux switches. Our BNFs are usually set up to arm on AUX1.
The Channel Map can be found in the receiver tab as well, and it is responsible for verifying what channels your sticks are on. If your throttle is set up on the wrong stick, please change the Channel Map to correct this issue.
For more details, please refer to
https://oscarliang.com/quad-arming-issue-fix/
https://betaflight.com/docs/wiki/getting-started/troubleshooting