sae_ext WPA3 is now supported in the wlan firmware and official Raspberry PIFoundation kernels with the brcmfmac driver as per https://github.com/raspberrypi/linux/pull/5945 and the kernel officially released today at https://github.com/raspberrypi/rpi-firmware/commit/7c3208cd25eea154e3fb3330ea32e29552bb131f
Could we add those patches to the OpenWRT kernels (and the required firmware files) for use on these devices?
Given the size of those changes to brcmfmac -and considering that brcmfmac is shared among many targets (at least bcm27xx, bcm53xx, imx, rockchip, sunxi, x86_64)- you really want to see those tickle down through mainline/ wireless-next first, or you run a huge risk of regressions for anything but the RPi (and a major source of pain for future kernel- or mac80211 updates). And that's before even checking the licensing state of the changes and firmware blobs.