Did you get it working yet? If not here is a post by MorrisseyJ that finally solved it for me. You can ignore the first part as you already have Ubuntu installed. I bolded the part that might be more relevant to your situation.
I didn't have a backup so haven't tried your solution.
I did however get this working another way. So here is another detailed solution. It should work but you will need a wired internet connection.
First you need to blacklist b43 so that you can get into the live session.
1. Boot to the live CD/USB
2. When the screen comes up showing the accessibility icon (little stick man and keyboard at the bottom of the screen), press any key
3. Pick your language, press enter
4. Press F6, this will launch a dialogue
5. Press esc to get rid of the dialogue
6. You should now have a cursor from which you can enter commands below the boot options: Type
making sure there is a space before and after the text you enter.
7. Press enter to either 'Try Ubuntu without installing' or 'Install Ubuntu'
In the case of the former, above, your instance of the live session should now work.
Now you should be able to install Ubuntu but you will still need to install b43 onto your system so that you can boot normally and use your wireless. To do this you have to boot to your system to do the install, but before that will work you once again have to blacklist b43 in the boot process. Here are the instructions.
1. Boot to the grub screen. If grub doesn't load automatically press, and hold, the Shift key after the BIOS screen (the screen mentioning your machine's manufacturer) disappears.
2. At the grub screen (the purple screen which lets you choose the instance of the kernel you want) press 'e', this will bring up a screen of text.
3. Using the arrow keys, navigate to the line which ends with "vt.handoff" or something similar. At the end of that line enter
again making sure to leave spaces before and after.
4. Press F10
This should boot you to your install, but your wireless won't be working. To fix this we have to install b43 - this is where you'll need your wired internet connection.
1. Open a terminal (ctrl+alt+t or hit the 'super-key' (the one with the windows logo on it) and type 'terminal' and press enter).
sudo apt-get install firmware-b43-installer
3. Enter your password (note your keystrokes won't register) and hit enter
Now b43 should install, your wireless should work and you should be able to boot without any problems.
Thanks to different people who helped me sort this out. Also, here is a blog detailing much of what needs to be done and which helped me get this sorted: http://linux-software-news-tutorials...s-because.html
Original link is here---->http://ubuntuforums.org/showthread.php?t=1966655