Where can I find this firmware file?

[lee]

I had the same trouble. The firmware is part of the bcmwl5.sys file, if 
you run the bcm43xx firmware program it will extract the firmware. Mine 
would only work some times. I want back to ndiswrapper for my wireless. 
I stoped bcm43xx from loading by adding the driver to blacklist file in 
/etc/modprobe.d diirectory. Now works fine all the time on 2.6.17-1.2145 
kernel.

Lee