I can confirme this bug too.
I found a work around when I was on Kubuntu 12.04 64bits : http://davidcortijo.wordpress.com/2012/05/07/ubuntu-12-04-how-to-solve-the-wifi-interface-using-ralink-rt3090-card/ Which fix the problem permanently, but since the upgrade to Kubuntu 12.04 64bits, the problem came back.
Lenovo B575
I can confirme this bug too.
I found a work around when I was on Kubuntu 12.04 64bits : davidcortijo. wordpress. com/2012/ 05/07/ubuntu- 12-04-how- to-solve- the-wifi- interface- using-ralink- rt3090- card/
http://
Which fix the problem permanently, but since the upgrade to Kubuntu 12.04 64bits, the problem came back.
Lenovo B575