Jul 09
Lost wireless after upgrading a Lenovo Ideapad U160 to Ubuntu 12.04
If you end up with no wlan after upgrading your Ideapad to Ubuntu to 12.04 Precise, then you are victim of a rare case: Ubuntu switched the wlan driver to an open source one for the b43 series of wireless card, like the Broadcom BMC4313 with PCI id 14e4:4727 that is used in the Ideapad U160.
But also, this firmware isn't free, so it isn't installed with the upgrade, leaving wlan in a non functional state.
To get wireless back, do this
sudo apt-get remove --purge bcmwl-kernel-source
sudo rm /etc/modprobe.d/blacklist-bcm43.conf
which deinstalls Broadcom STA related stuff that might have been installed before. Then make sure that the broadcom drivers aren't blacklisted in /etc/modprobe.d/blacklist.conf (look for things with "43" in the name, or "br cm")
and after that:
sudo apt-get install linux-firmware-nonfree
sudo reboot
And your wireless should be up after the next reboot!
Alternatively:
If this doesn't help, try your luck with the STA proprietary driver. (Which is the reverse of what we did above):
sudo jockey-gtk
Select the STA driver