Why did Unity stop working after I upgraded to the 3.4.3 mainline kernel?

Question

I installed the latest Linux kernel (3.4.3). After rebooting, it says I am in Ubuntu 2D. How do I either go back to my previous kernel, or fix this problem? Thanks.

$ uname -r
3.4.3-030403-generic

Answer 1

This kernel apparently lacks drivers needed for Unity support, as it's a mainline kernel without Ubuntu added code and drivers.

To go back to your old kernel:

• Reboot and right after your system finishes the self-test (POST) routine, press the left shift key and keep it pressed until you get to the GRUB menu.
• Select "Previous Linux versions" and boot with a 3.2-series kernel

• If you want to remove the non-working kernel, open a terminal and type

  sudo apt-get remove linux-image-generic=3.4.3