When you will upgrade from 2.4 to 2.6 you need to add one line your GRUB/LILO .
initrd and /path ..
For that you need to generate the initrd image also.
So add this line and reboot it.
We are now using kernel 2.4.31.
We are trying to upgrade the kernel to 2.6.17.
The compilation was fine, but booting was impossible.
The last error message on console was the following.
"Warning : Unabe to open an initial console"
I attached the whole screen of the console.
Could you please check this problem ?