Solved Late-2009 MacMini, Broadcom BCM4321 wireless

So long as you don't mind running FreeBSD 12.0-CURRENT #1 r329009M and apply the patch in the following wireless mailing list post I'm extremely happy to report that my MacMini no longer needs a cheap Chinese pocket router attached to the ethernet port but actually uses the inbuilt Broadcom BCM4321 wireless adapter on the 5G band :)

Thanks to Landon J Fuller for the miracle patch!