To do this you must append the noapic command to the kernel line for the particular md.
You will need to be root on the core
sudo su -
You will also need to know the MAC address of the MD in question. You can either view this on the Media Directors page in the web admin, or by running:
ifconfig | grep HWaddr
Once you have this info, edit the config file located here :
You should see a text file, or config file for your MD's MAC address.
use your favorite editor, I prefer vi:
Find this line:
APPEND initrd=70/initrd.img quiet splash ramdisk=10240 rw root=/dev/nfs boot=nfs nfsroot=192.168.80.1:/usr/pluto/diskless/YOUR MD NUMBER
And add it before the ramdisk entry.
Save the file, and reboot the MD.
That should sort it for you.