>Jaunty might no longer detect your webcam after the installation. That was what happened to me. If you’re a heavy webcam user and can’t give up video chatting in Skype or Empathy, you can safely skip this post.
Here’s the latest hybrid I’ve done. If for one reason or another you’re still refusing to upgrade to Karmic, you might be interested in splicing in Karmic’s kernel (2.6.31.6) into Jaunty. I’ve tried it and worked flawlessly, but the performance boosts can rival that of Karmic.
Follow the steps below:

1. Click this link and download the full version of Karmic’s kernel. It should be in .tar.bz2 extension. At the time of writing, the latest stable version is 2.6.31.6 and that was what I tried out in Jaunty. You’re free to try later ones if you wish.
2. Place it somewhere in your directory and untar it with the following command: tar xjvf linux-2.6.31.6.tar.bz2 -C /usr/src
   This will unpack the file into your /usr/src folder as linux-2.6.31.6 folder.
3. Depending on your machine, you might need to install additional libraries before you can proceed. In my case, I needed the GCC compiler and three additional development packages as follows: sudo apt-get install gcc libgtk2.0-dev libglib2.0-dev libglade2-dev
4. cd into linux-2.6.31.6 folder and the first command if you’re running GNOME, or the second one if KDE. make gconfig
   make xconfig
   The above commands serve as configuration tools if you’re interested in adjusting kernel’ options (over 1,000!). Otherwise you can skip this step.
5. Compile the kernel image. This is the fun part, as it may take hours, so make time! make
6. Compile the kernel modules. Hopefully this should only take seconds. make modules
7. Install the kernel modules as sudo. sudo make modules_install
8. Install the kernel itself. make install
9. After the above step, you should be able to find three files in your /boot directory: System.map-2.6.31.6, config-2.6.31.6, vmlinuz-2.6.31.6
10. You now need to create an initrd kernel image to boot Jaunty with. This can easily be done by issuing the following command in your /boot directory. sudo mkinitramfs -o initrd.img-2.6.31.6 2.6.31.6
    In case you’re wondering why the command is called mkinitramfs instead of mkinitrd, the latter has been deprecated, so don’t use the old one.
11. That should take care of the kernel installation. As a last step, you’ll need to modify your GRUB menu to point to the new kernel image. sudo gedit /boot/grub/menu.lst
12. Add the following lines into the file.

    title Ubuntu 9.04, kernel 2.6.31.6
    uuid zzzzzzzzz
    kernel /boot/vmlinuz-2.6.31.6 root=UUID=zzzzzzzzz ro quiet splash
    initrd /boot/initrd.img-2.6.31.6
    quiet Make you sure replace zzzzzzzzz with your uuid that you can find in the file.

13. Once that’s done, reboot the system. Find the kernel image in the GRUB menu and boot into it. Enjoy!