Changing access point configuration from WEP to WPA gotcha
I just wasted 6 hours of my life fixing something that I apparently broke. Hopefully Google picks this up and I can help other unfortunate souls.
I decided to reconfigure my AP to use WPA instead of WEP. While I was fiddling with the web based configuration a Windows laptop somewhere in my house was connected to the AP. I foolishly enabled both WPA and WEP on my AP, and the Windows wi-fi driver (for a Broadcom 4306 on an HP notebook) threw a fit and disconnected the notebook.
I realized my mistake and enabled only WPA, but another machine had issues so I went back to my original WEP settings. So the HP should just work, right?
No. It could connect to the network with trouble. This seemed strange because the signal strength was as good as always. After a while it disconnected me, and then slowly reconnected. Figuring that I broke something in Windows I rebooted in Ubuntu since I just needed to do some web browsing. Imagine my surprise when Ubuntu exhibited the same behaviour. My other WEP connected machines were fine but this notebook had somehow mysteriously been broken on a hardware level.
After struggling in Ubuntu for hours I went back to Windows - still broken. I downloaded a recent Broadcom driver, installed it and it all worked! Even better, rebooted in Ubuntu and it worked there as well! This means the Windows driver did something to firmware on the wi-fi adapter when it encountered that first WEP / WPA error.
Moral of the story: disable all connectivity to an AP completely before reconfiguring its connection method.
