See http://sprunge.us/UNGF (2010.04 dmesg)

[   81.950080] b43 ssb0:0: firmware: requesting b43/ucode5.fw
[   81.998606] b43 ssb0:0: firmware: requesting b43-open/ucode5.fw
[   82.008771] b43-phy0 ERROR: Firmware file "b43/ucode5.fw" not found
[   82.008776] b43-phy0 ERROR: Firmware file "b43-open/ucode5.fw" not found
[   82.008780] b43-phy0 ERROR: You must go to 
http://wireless.kernel.org/en/users/Drivers/b43#devicefirmware and download the correct firmware for this 
driver version. Please carefully read all instructions on this website.