I’ve written before about Mac OS X Lion Wi-Fi problems, suggesting that people can try to fix them by using the Wi-Fi driver from Mac OS X Snow Leopard instead. It doesn’t work for everyone, and I never offered a way to go back to the Lion driver that you were running if things didn’t improve.
I’ve recently updated the copy of the OS X Snow Leopard Wi-Fi driver that I linked to with a couple of shell scripts to backup and restore the version of the driver you’re currently running, before you attempt to use the Snow Leopard version.
The scripts are fairly dumb, and in the restore script’s case it doesn’t actually restore the driver and gives you the list of commands I think you should use to do so instead. They work perfectly fine for me, but since they involve manipulation of OS X’s kext cache, I’m leaving it up to you to type those in to a running terminal.
Given that it’s a fairly low-level system operation, I’ve resisted the temptation to develop a higher-level solution that’s more resilient and can be operated solely with your administrator password. Partly out of laziness I admit, but partly out of a desire to have people learn about the excellent Unix shell environment and system utilities underneath the OS X GUI environment. It can be used to do all manner of interesting things to and with your Mac system.
If you’re in doubt about any of the things I’ve said, since I know there are non-technical OS X users looking for a solution, I really encourage you to go and learn about them. The underlying shell environment isn’t scary.
Search for terms like kextcache, sudo, zsh and Terminal.app to get started, and read as much as you can.
Feel free to ask questions here in the comments below, on Twitter to @ryszu, or via email as some of you have been doing (hi, Joel, sorry this is late!).