How to enable WIFI on first firmware boot by default?

Hello,
How to enable wifi by default in firmare? Maybe it's possible changing some settings in source code?
I need this because wired LAN is not working on my router, so I will not need to access it using serial connection while fixing wired LAN issues.

You can simply build an image that includes your own custom network configuration file with wireless enabled

https://wiki.openwrt.org/doc/howto/build#custom_files