From http://thanhsiang.org/faqing/node/129 Here is the summary of the steps (replace with your desired kernel versions). 1. Download the working kernel files: wget http://launchpadlibrarian.net/19976056/linux-image-2.6.27-9-generic_2.6.27-9.19_i386.deb wget http://launchpadlibrarian.net/19976058/linux-headers-2.6.27-9-generic_2.6.27-9.19_i386.deb wget http://launchpadlibrarian.net/19976059/linux-headers-2.6.27-9_2.6.27-9.19_all.deb 2. Next, install the three downloaded DEB files with dpkg: sudo dpkg -i linux-* 3. Reboot your computer. 4. Put your current kernel on hold (otherwise it would be upgraded once again during your next "aptitude update && aptitude safe-upgrade" routine): sudo aptitude hold linux-image-2.6.27-9-generic linux-headers-2.6.27-9-generic linux-headers-2.6.27-9 Note: https://launchpad.net/ubuntu/intrepid/+package/linux-image-2.6.27-9-generic https://launchpad.net/ubuntu/intrepid/i386/linux-headers-2.6.27-9-generic/2.6.27-9.1...