It has been more than two weeks since I upgraded from Mountain Lion to Mavericks on my old MacBook Pro. It is also more than two weeks since the upgrade broke my Wi-Fi. The Wi-Fi actually worked for a while before it went dead. A subsequent reboot resulted in the indicator showing "Wi-Fi: No hardware installed".
I have tried all the advices and solutions I could google. I tried anything from resetting the SMC/NVRAM/PRAM to doing a clean reinstall of the operating systems. Downgrading to Mountain Lion or using a USB network adapter did not help too. These had me thinking whether Mavericks had killed my Wi-Fi or my Wi-Fi is no longer supported with any device driver. Maybe it's the VirtualBox update I did but highly unlikely since I reinstalled...
Hence in comes the TL-WR702N by TP-LINK, a 150Mbps wireless N portable router. My friend happened to have one on hand so we gave its client mode a try. The client mode allows the router to be connected to another device via Ethernet core and acts as an adapter to send/receive the wireless signal from a wireless network.
It worked! Therefore I went out to get myself one for S$34. It is supposed to be a stopgap fix but with no solution in sight, apart from buying a new MacBook, I think I may have to carry the router around with me for good.