What magic string do I put in local.conf to get the 80211 (cfg80211.ko in particular) to get built in my image?
you have 2 methods to get cfg80211.ko module.
1. In Yocto
#bitbake -c menuconfig linux-imx
Use the command to load kernle menu and select M for cfg80211 option.
Refer to i.MX_Linux_Users_Guide.pdf, use standalone method to compile linux kernel and device tree.
# make menuconfig
Use the command to load kernel menu and select M for cfg80211 option.
open i.MX_Linux_Users_Guide.pdf and search standalone, you will find related chapter.
Actually, you can compile u-boot and kernel image by standalone, and use yocto to compile rootfs.
Hope this information is helpful to you.
Have a nice day!