Problem about wifi firmware on android

I tried to porting android on beagleboard based on the document - for
their sharing), I met a problem about wireless network. I make module
for wireless(zd1211) and insmod it successful. But when I tried to
wake up the network(netcfg wlan0 up), it cannot find zd1211 firmware.
I placed it on /system/lib/zd1211 and symblink it to /lib, still no
use. I have no idea about how to do, can anyone give me some advice?

Thank you!!