I've resolved this problem with a workaround: I found a
TPLINK r8188eu based usb wifi adapter that I managed to get
working with little fuss. So I'm back to my regular wifi
setup script using netaid (below). I also blacklisted
the wl and b43 drivers which I won't be needing.

FWIW, the router is flashed with openwrt, and configured
as recommended by apple:

https://support.apple.com/en-us/HT202068

#!/bin/sh
IF=wlan1
sudo netaid 5
sudo killall wpa_supplicant
sudo wpa_supplicant -B -i $IF -c /etc/wpa_supplicant.conf &
sleep 2
sudo ifdown $IF
sleep 1
sudo ifconfig $IF down
sleep 1
sudo netaid 4 bliss


cheers and thanks again for much helpful advice

joel

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