Kernel Versions
generic=Generic (all). needs matching modules installed to boot
si=Southern islands HD7750, R7,R9
ni=Evergreen and Northern islands HD5450,HD6570,HD6670
rv=Radeon HD4650 and HD4850 etc
The installer installs the Generic version of the kernel  and modules .
To change the installed kernel version  unpack the kernel archive and copy the required kernel version to  /boot.
you must edit the /boot/menu.lst file to match the new kernel version.
Also if the kernel version is not the same one installed by the installer you must copy the modules for the new kernel  to /lib/modules/.
you must be root to do the copy. Use su for Debian or sudo for Lubuntu .

Examples

title Debian Jessie - kernel 3.18-14-si 
kernel /boot/uImage-3.18.14-si root=/dev/sda9 console=ttyS0,115200 console=tty0 
dtb /boot/canyonlands.dtb

or

title Debian Jessie - kernel 3.18-14-ni 
kernel /boot/uImage-3.18.14-ni root=/dev/sda9 console=ttyS0,115200 console=tty0 
dtb /boot/canyonlands.dtb
