I'll post the reply I was given to solve this problem, just in case somebody comes across the same thing
To fix this you have to recompile the kernel:
Start with the kernel configuration of your actual kernel image. To get your
kernel configuration just boot into your whiite linux installation and do a:
zcat /proc/config.gz > /tmp/my_kernel_config.txt
This will create a file
named /tmp/my_kernel_config.txt, which you need to copy to your "build" machine
(i.e. where you will build/compile your kernel).
Then follow the instructions at:
[
www.gc-linux.org]
At step 2 of "Building the kernel image", instead of using a default config, do
copy the contents of your my_kernel_config.txt file to linux-2.6.32/.config .
Then modify the .config file to set the needed option (CONFIG_BLK_DEV_SR=y). The
.config file is a text file that you can manually edit. Alternatively, if you
prefer it, you can do a "make menuconfig" to tweak the options.
I got to thank for this to Albert Herranz!