10.5.2 update "killed" the Airport wireless connection to a Verizon Westell VersaLink 327W wireless DSL router on a friends MBP (with "n"). After several tries at deleting keychains, reinstalling combo updates, etc., it all pointed to the router itself. That's usually the case, but it's obviously frustrating when it "worked" with a previous version. Found the latest firmware and applied it - once again, all is happy in wifi land. For reference: Model number: a90-327w15 Firmware version (now): 4.04.03.00 edit: Verizon's Firmware download site I hope this helps others using the Westell modem. edit 2: just saw exact same model fixed with firmware update earlier this evening over at MacFixit.