Recently I started doing some interesting security work. I downloaded a great series from Vivek Ramachandran on 802.11 Wireless Hacking. For the series, he suggested using the Alfa Networks AWUS036h card. Because I have a wedding coming up and I need to save money, I wanted to see if I could get it working without that since I had an old USB dongle from NetGear (WG111v1). When I plugged it in initially to my BT5 VM, it brought up the error message “(p54usb) cannot load firmware isl3887usb (-2)”. Using ndiswrapper is a fine way to go if you never plan on using monitor mode with the network card but for the tutorial series, I needed to have this capability. To solve this issue, simply use the following command and you’ll be good to go with your wireless adapter if it can use the p54 driver.
apt-get install linux-firmware-nonfree

This was all discovered after several hours of building drivers, realizing that I accidentally downloaded the x64 version of BT5 (which is why the drivers weren’t working), ndiswrapper doesn’t (and won’t ever) support monitor mode.