As part of reviving my MacBook 4,1 (or early 2008 / A1181) on which I decided to install FreeBSD, I encountered some difficulties with the wifi adapter.
bwn_pci0@pci0:2:0:0: class=0x028000 rev=0x03 hdr=0x00 vendor=0x14e4 device=0x4328 subvendor=0x106b subdevice=0x0088 vendor = 'Broadcom Inc. and subsidiaries' device = 'BCM4321 802.11a/b/g/n' class = network Here are the steps I had to go through to get it working.
First a custom kernel has to be build with the BWN_GPL_PHY option that allows to build some GPL-licensed portions of the driver code base.