I got the following Error:
device not ready(firmware missing)
To solve this, first check if wireless driver is installed in your system.
Check for wireless driver in the following path:
Applications-> System Tools-> System settings->Additional Driver
If it is present and activate it.
If not, we need to install the driver. Use the following commands for the same and you are done!
$ sudo apt-get install firmware-b43-installer
$ sudo apt-get install firmware-b43-lpphy-installer