Build target with different board

HI is there a short guide somewhere

to modify my target config or/and kconfig to select a different SOC.

As an example SOC ar9340 as the soc for gl-ar150 instead of SOC ar9330 or ar9331 ?

(Moved to the For Developers section.)

There is no guide for that. You need to define low level hardware controls rather deeply.

Gl-ar150 has its chip drivers defined here:;a=blob;f=target/linux/ar71xx/files/arch/mips/ath79/mach-gl-ar150.c;h=9febc7a839262254907f3aa31f4cff6ba94097b0;hb=HEAD

That is one of the places that you likely need to change

I noticed that you have another rather detailed thread about your trials. Based on that, my earlier advice above looks rather unnecessary. But still, there is no practical guide for you.