To install the necessary firmware to use the Rosewill RNX-N150UBE USB wireless adapter in Ubuntu:
1. Disconnect the adapter.
2. Connect to the internet (using an ethernet cable or another wireless card)
3. In a terminal window, enter the following three commands:
# wget http://svn.debian.org/wsvn/kernel/dists/trunk/firmware-nonfree/realtek/RTL8192SU/rtl8192sfw.bin # sudo mkdir /lib/firmware/RTL8192SU # sudo cp rtl8192sfw.bin /lib/firmware/RTL8192SU
4. Re-connect the adapter
The exclusion of this firmware is a known bug.