1, First, use another computer to download b43 firmware into USB stick driver and drag it on your desktop:
http://downloads.openwrt.org/sources/broadcom-wl-4.80.53.0.tar.bz2
2, click to extra the file. Now it’s folder: broadcom-wl-4.80.53.0.
3, Use terminal to write the command lines to enter the ‘kmod’ folder in the ‘broadcom-wl-4.80.53.0’ folder. The command can be:
cd ‘Desktop/broadcom-wl-4.80.53.0/kmod’
It depends on the location of the folders.
Then:
sudo b43-fwcutter -w /lib/firmware ~/ wl_apsta.o
if can’t find b43-fwcutter, go to instal CD or USB Live Driver. Under the folder pool/main, you will find b43-fwcutter, click to install it.
Then the files will be extracted and copied to /lib/firmware/b43
Next:
sudo modprobe b43
Reboot the computer, and then the wireless will be back.
It works for me 🙂