After installing Fedora 23 Linux, I had to do a few steps to get my wifi adapter working, which is a Broadcom BCM43228 card. It turns out that these steps have to be repeated each time after a kernel update.

Short version

Those steps are automated in this script, which can be executed as the root user:

su - # or `sudo su -`, depending on your Linux distro
dnf upgrade && reboot # to avoid an error while building the driver (see Step 2 in the long version)

su -
cd /var/tmp
wget https://gist.github.com/ouyi/d7768d21fa9dfc6d27b0/raw/250aea83cc7b09d99c01fe41e50249c9702082e7/fedora23_broadcom_wl.sh
chmod +x ./fedora23_broadcom_wl.sh
./fedora23_broadcom_wl.sh

After that I was able to onnect to my Wi-Fi network via the NetworkManager.

Long version

The solution basically consists of three steps:

  1. Download the driver

    The Linux driver can be downloaded from the Broadcom site. According to the README The driver supports (but not limited to) these cards :

     BCM4311
 BCM4311
 BCM4311
 BCM4312
 BCM4313
 BCM4321
 BCM4321
 BCM4321
 BCM4321
 BCM4322
 BCM4322
 BCM4322
 BCM43142
 BCM43224
 BCM43225
 BCM43227
 BCM43228
 BCM4331
 BCM4360
 BCM4352

  2. Build and install the driver

    Run a dnf upgrade and reboot first, to avoid the following error while building the driver:

     error: make[1]: *** /lib/modules/4.2.3-300.fc23.x86_64/build: No such file or directory. Stop.

  3. Load the driver

    A depmod -a was needed to make the newly installed driver available to the modprobe command and to avoid missing dependency issues like the following:

     [ 1350.902636] wl: module license 'MIXED/Proprietary' taints kernel.
 [ 1350.902649] Disabling lock debugging due to kernel taint
 [ 1350.913297] wl: module verification failed: signature and/or required key missing - tainting kernel
 [ 1350.913486] wl: Unknown symbol cfg80211_inform_bss_frame_data (err 0)
 [ 1350.913538] wl: Unknown symbol cfg80211_scan_done (err 0)
 [ 1350.913597] wl: Unknown symbol cfg80211_disconnected (err 0)
 [ 1350.913646] wl: Unknown symbol wiphy_new_nm (err 0)
 [ 1350.913679] wl: Unknown symbol wiphy_register (err 0)
 [ 1350.913709] wl: Unknown symbol cfg80211_put_bss (err 0)
 [ 1350.913737] wl: Unknown symbol cfg80211_roamed (err 0)
 [ 1350.913767] wl: Unknown symbol cfg80211_gtk_rekey_notify (err 0)
 [ 1350.913801] wl: Unknown symbol cfg80211_ibss_joined (err 0)
 [ 1350.913836] wl: Unknown symbol cfg80211_michael_mic_failure (err 0)
 [ 1350.913865] wl: Unknown symbol cfg80211_connect_result (err 0)
 [ 1350.913901] wl: Unknown symbol wiphy_unregister (err 0)
 [ 1350.913934] wl: Unknown symbol cfg80211_get_bss (err 0)
 [ 1350.913969] wl: Unknown symbol __ieee80211_get_channel (err 0)
 [ 1350.914022] wl: Unknown symbol ieee80211_channel_to_frequency (err 0)
 [ 1350.914055] wl: Unknown symbol cfg80211_report_wowlan_wakeup (err 0)
 [ 1350.914139] wl: Unknown symbol cfg80211_inform_bss_data (err 0)
 [ 1350.914169] wl: Unknown symbol ieee80211_frequency_to_channel (err 0)
 [ 1350.914207] wl: Unknown symbol wiphy_free (err 0)

References

The solution is based on this page.

This one does not work for me.

Update 21st Oct 2016

Unfortunately, the recent kernel update to 4.7.7 broke the above method. The build process fails with this message:

cfg80211 api is prefered for this kernel version ieee80211_BAND_2ghz undeclared

Selecting the previous kernel version (4.5.6 in my case) from the boot menu allows me to still work with wifi.