Wireless device for HP NoteBooks users who owns ProBook5420s, config

I have HP NoteBooks ProBook5420s. There is a little problem with driver in KUbuntu.

lspci|grep "Network controller:"
44:00.0 Network controller: RaLink RT3090 Wireless 802.11n 1T/1R PCIe

In spite of that the controller is RT3090 it works with rt3390sta driver.
lsmod |grep rt
rt3390sta 1153989 1

My attemts to enable wireless networking with rt3090sta driver were unsaccessfull.

Ram diska creation

Ram diska creation. It is very usefull if you like wardriving:)

# mkdir /tmp/ramdisk; chmod 777 /tmp/ramdisk

# mount -t tmpfs -o size=256M tmpfs /tmp/ramdisk/
or
# mount -t tmpfs tmpfs /tmp/ramdisk -o size=1G,nr_inodes=200k,mode=01777