I have tried this out on "Linux Mint 9 Isodora" LiveCD and the wireless card (BCM4312 b/g rev 01) works perfectly well.

The broadcom 43XX series chips all need firmware loaded before it can operate. I got this infomation from linuxwireless.org. But the firmware is proprietary stuff thus cannot be included in the distribution.

I was just  wondering why not just point this out instead of prompting users to installing two other proprietary drivers like "sta". According to directives from linuxwireless.org, b43 supports many features those proprietary drivers aren't capable of.

So the solution is to install the firmware, then reload the b43 module. A few seconds later, the card should be able to find any available signal around. Instructions on how to install the firmware is included in the link at bottom of the tutorial. Reload the b43 module is simple. Just type commands below in a terminal with root privilege.

modprobe -r b43 && modprobe b43

Here is my situation, I need to boot Isodora from USB drive in LiveCD mode, and I only got wireless access to the Internet. So there is a Catch-22, i.e. I need to bring up the card and connect to the repository to download those .deb packages, but bringing up the card needs those packages first.

Hopefully, I should be able to extract those firmware files and place them to the right place manually without using those apt things. Luckily it's easy and clean. just copy the directory in /lib/firmware/b43/ to USB drive and restore them into /lib/firmware/ of the LiveCD, then reload the b43 module. Seconds later, everything should be working. :)

Instructions on how to install firmware for Broadcom chips and other stuffs.

http://linuxwireless.org/en/users/Drivers/b43